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golf nut
10-09-2009, 04:25 AM
Why are skimmers rated for system gallons rather than for bio-load? A 200 g system has little load compared to a fish only 100g

banditpowdercoat
10-09-2009, 04:55 AM
I wana know too. And why, are some WAY more expensive than others? Cause it's made in Germany, means it's 3x the price?

sphelps
10-09-2009, 05:25 AM
Why are skimmers rated for system gallons rather than for bio-load? A 200 g system has little load compared to a fish only 100g
Why not ask the skimmer manufacturer? Aren't they the experts?

banditpowdercoat
10-09-2009, 05:30 AM
Why not ask the skimmer manufacturer? Aren't they the experts?

Is because you make something, does that instantly make you an expert? :D

Myka
10-09-2009, 01:38 PM
The ratings are ridiculous. I think a BakPak is rated for 100 gallons or something stupid like that. It seems the lower the quality, the higher the rating. I think it's something you just need to get a feel for. Also, a lot of people think that if they have a 180 gallon tank that a skimmer that is good for 180 gallons is a perfect match. Well, that's just silly, you're running the skimmer as MAX suggested volume?? The skimmer should be bigger than the water volume.

sphelps
10-09-2009, 02:34 PM
Is because you make something, does that instantly make you an expert? :D
Nah that's not what I was getting at, I'm certainly no expert. It was sarcasm, kind of an inside joke to another thread :wink:

Skimmer ratings will never be accurate, what works for one won't work for another. The ratings are general guidelines and some common discretion is required from the buyer. However for the most part skimmer ratings aren't that off for the major brands (cheap novelty brands aside). I've used a Euro Reef 180 on a ~250 gallon decently stocked reef tank and it worked well for the system. Also your skimmer dependence actually decreases with a fish only, yes you can use a larger one and it can be beneficial but the higher nutrients won't necessarily cause a problem. Many people with FOWLR tanks don't even use skimmers and do quite well.
I can't see a bio-load rating being practical, how exactly do you rate bio-load? Either way it's common sense, if you plan on having a higher than normal bio-load for your tank you always have the option of using a larger skimmer. One could simply assume the rating is based on a standard load for the given volume.

Gizmo
10-09-2009, 04:12 PM
Just an off the cuff though, could you not rate a skimmer based on ml/hour of "dense" skimmate (i know dense is a relative term) so at least all skimmers are on a level playing field. You could then calculate how many ml/hr you would need based on your bioload and needs. (no I don't know what that calculation would be, but it wouldn't take much other than experimenting with a baseline skimmer, and varying bio-loads to come up with an approximation)

sphelps
10-09-2009, 04:45 PM
Just an off the cuff though, could you not rate a skimmer based on ml/hour of "dense" skimmate (i know dense is a relative term) so at least all skimmers are on a level playing field. You could then calculate how many ml/hr you would need based on your bioload and needs. (no I don't know what that calculation would be, but it wouldn't take much other than experimenting with a baseline skimmer, and varying bio-loads to come up with an approximation)
I wouldn't want to be that sales guy trying to sell those skimmers :wink:
Simpler is usually better and specifying specifics like that will cause huge issues as results will always vary. It's one thing to say this skimmer will typically handle 200 gallons of tank volume but to say this skimmer will produce X amount of skim mate is another story. There are certainly skimmers out there that have bad ratings, seaclones are one that come to mind, but good quality skimmers are rated fairly decent in my books, and on occasion some manufacturers do actually give a few rated volumes based on high and low bio-loads.
I think too much thought is going into this, consider all the variables involved in actually determining the right skimmer. Amount of fish and other livestock, size of fish and other livestock, type of fish and other livestock, amount of food feed, allowable nutrient level (sps-low, lps-med, fowlr-high), tank volume, and so on. I mean these ratings are just general guidelines, just like fuel ecomony ratings on cars, they aren't that accurate either but there are too many variables involved for it to be accurate for each person.

banditpowdercoat
10-09-2009, 05:05 PM
One thing I know, BOTH my skimmers suck, and Im to broke to get BK's LMAO

fkshiu
10-09-2009, 05:26 PM
Tunze gives you a little more help by listing a "maximum" tank size for their skimmers which you subtract down from depending on what you are keeping in the tank (e.g. SPS, LPS, softies, FO).

mark
10-09-2009, 07:46 PM
little dated and yes could be problems but here:

http://www.aquariumcontrollers.com/aquarium-equipment-comparisons.php#skimmerchart

lastlight
10-09-2009, 07:56 PM
Best they can do is give you ballpark ideas and then you ask people who have experience with them I think.

untamed
10-09-2009, 08:03 PM
I'm recalling that study that recently tried to measure WHAT was being removed by skimmers and how quickly various models removed it.

I believe that their conclusions were that the "larger" skimmer (the one the processed a larger volume of water per hour) removed the measured stuff more quickly, but that all the skimmers tested reduced the measured stuff to about the same level given time.

It struck me that a big difference between the test environment and an actual aquarium is that the aquarium continually generates new waste so a truly undersized skimmer won't ever get the chance to catch up and waste could accumulate.

Yes, I agree...it is more about bioload than actual water volume.

IMHO, size matters. In order to increase the amount of water it can process per hour, the chamber needs to get bigger. Increasing the flow rate with a smaller chamber just reduces the amount of time the water is in contact with the air bubbles (dwell time). In my case, I wanted to get to 1.5x tank volume per hour (600gph) with 2 minute dwell time inside the skimmer. That means that I need to have a 20 gallon chamber....yikes!

After that, I didn't really pay attention to what the skimmer says it is rated for.

golf nut
10-09-2009, 11:01 PM
BK will tell you in a heartbeat that you can overdo skimming by buying a unit that is oversize, it simply doesn't work, or should I say doesn't work properly.

I know there is a distinct difference between having the skimmer in the tank with no sump as compared to having a sump with a 10 times turnover, it just isn't the same, the tank install though ugly will work better every time, explaining it is a different matter.

Palmer
10-10-2009, 04:23 PM
BK will tell you in a heartbeat that you can overdo skimming by buying a unit that is oversize, it simply doesn't work, or should I say doesn't work properly.

I know there is a distinct difference between having the skimmer in the tank with no sump as compared to having a sump with a 10 times turnover, it just isn't the same, the tank install though ugly will work better every time, explaining it is a different matter.

If the tank install works better every time then is it reasonable to assume a hang on the back skimmer on the main tank is also better than an in sump set up?

Palmer

sphelps
10-10-2009, 05:48 PM
In sump works better because of the overflow effect. The high specific gravity in salt tanks results in proteins/organics rising. the idea of the sump and overflow system is that the overflow constantly sends the top water from the display to the sump.

steveg
10-11-2009, 05:20 AM
Hi there, so you are suggesting that the best way to operate a skimmer is to take water directly from the display tank and return it there instead of doing that from the sump?





BK will tell you in a heartbeat that you can overdo skimming by buying a unit that is oversize, it simply doesn't work, or should I say doesn't work properly.

I know there is a distinct difference between having the skimmer in the tank with no sump as compared to having a sump with a 10 times turnover, it just isn't the same, the tank install though ugly will work better every time, explaining it is a different matter.

robert
10-13-2009, 01:53 AM
Brad - I like your theory, it makes sense to me. I have a question though. Which of those 2 parameters is more tweak-able/forgiving - tank volume per hour or dwell time?

For example, I have ASM 5G with about 6gal cylinder capacity. Manufacturer suggested system size for this one is 700gal. Granted, real life users would not put this skimmer on anything bigger than 350-375gal. Now, applying your theory, keeping flow at 1.5x volume of the tank with 2 min. dwell time this skimmer is no good for anything bigger than 120gal. Which parameter would you tweak for bigger system? Volume per hour or dwell time? No, "Get a bigger skimmer" is not applicable answer at this time.

Thanks a lot.

Cheers.




I'm recalling that study that recently tried to measure WHAT was being removed by skimmers and how quickly various models removed it.

I believe that their conclusions were that the "larger" skimmer (the one the processed a larger volume of water per hour) removed the measured stuff more quickly, but that all the skimmers tested reduced the measured stuff to about the same level given time.

It struck me that a big difference between the test environment and an actual aquarium is that the aquarium continually generates new waste so a truly undersized skimmer won't ever get the chance to catch up and waste could accumulate.

Yes, I agree...it is more about bioload than actual water volume.

IMHO, size matters. In order to increase the amount of water it can process per hour, the chamber needs to get bigger. Increasing the flow rate with a smaller chamber just reduces the amount of time the water is in contact with the air bubbles (dwell time). In my case, I wanted to get to 1.5x tank volume per hour (600gph) with 2 minute dwell time inside the skimmer. That means that I need to have a 20 gallon chamber....yikes!

After that, I didn't really pay attention to what the skimmer says it is rated for.

littlesilvermax
10-13-2009, 03:19 AM
I agree that too big of a skimmer can happen, in real life it rarely happens, unless you are rich (or used to be).:wink:

Look at others that have exceptional systems, see what they use and copy them. Don't be afraid to spend a fair chunk of change, it is a very important part of the tank. And, unlike lighting, doesn't keep whacking your wallet with additional costs (cept monthly electricity).

untamed
10-13-2009, 05:42 AM
Brad - I like your theory, it makes sense to me. I have a question though. Which of those 2 parameters is more tweak-able/forgiving - tank volume per hour or dwell time?

For example, I have ASM 5G with about 6gal cylinder capacity. Manufacturer suggested system size for this one is 700gal. Granted, real life users would not put this skimmer on anything bigger than 350-375gal. Now, applying your theory, keeping flow at 1.5x volume of the tank with 2 min. dwell time this skimmer is no good for anything bigger than 120gal. Which parameter would you tweak for bigger system? Volume per hour or dwell time? No, "Get a bigger skimmer" is not applicable answer at this time.

Thanks a lot.

Cheers.

Yup, that is the math...If the chamber size is constant, then increasing flow rate (tank turnover) reduces dwell time and vice-versa. Assuming that you have re-circ'd the G5, then you can control the flow rate. If you haven't re-circ'd, then your flow rate is set by the amount of water drawn in by the NW pumps and you would have no control over it.

Really, controlling flow rate is one of the big reasons why one might choose a recirc skimmer over a non-recirc skimmer.

Given the limitation of the size, I would be inclined to try decreasing flow rate for increased dwell time. Playing with the flow rate a bit is certainly worthy of experimentation for sure.

Plus...if you wanted to increase the chamber size, you can have my old G6 body if you like.

robert
10-13-2009, 06:03 AM
Brad - yes, re-circ'd is what I have done to G5. You have PM :biggrin:
Cheers.

Yup, that is the math...If the chamber size is constant, then increasing flow rate (tank turnover) reduces dwell time and vice-versa. Assuming that you have re-circ'd the G5, then you can control the flow rate. If you haven't re-circ'd, then your flow rate is set by the amount of water drawn in by the NW pumps and you would have no control over it.

Really, controlling flow rate is one of the big reasons why one might choose a recirc skimmer over a non-recirc skimmer.

Given the limitation of the size, I would be inclined to try decreasing flow rate for increased dwell time. Playing with the flow rate a bit is certainly worthy of experimentation for sure.

Plus...if you wanted to increase the chamber size, you can have my old G6 body if you like.

golf nut
10-13-2009, 11:58 AM
Hi there, so you are suggesting that the best way to operate a skimmer is to take water directly from the display tank and return it there instead of doing that from the sump?

I am suggesting that you have the sump turnover rate at the correct volume to get maximum results from the skimmer, typically this will be a lot less than the previously suggested 10x rate.

sphelps
10-13-2009, 02:33 PM
I am suggesting that you have the sump turnover rate at the correct volume to get maximum results from the skimmer, typically this will be a lot less than the previously suggested 10x rate.
But you can't explain why? Just cause, right?

Canadian
10-13-2009, 06:47 PM
This is somewhat dependent on your sump layout but think of this analogy:

If I drop a small piece of sinking pellet food down my overflow and I have one of two options:

a) High flow rate through my sump
b) Low flow rate through my sump

Which one do you think is most likely to allow the intake/suction of the skimmer intake to pull in the piece of food? The one ripping the current past the skimmer or the one slowly plodding along?

I'd certainly rather pull mechanical chunks of organic waste out of my tank before they have a chance to break down and then become part of the chemical soup in the water.

sphelps
10-13-2009, 07:34 PM
This is somewhat dependent on your sump layout but think of this analogy:

If I drop a small piece of sinking pellet food down my overflow and I have one of two options:

a) High flow rate through my sump
b) Low flow rate through my sump

Which one do you think is most likely to allow the intake/suction of the skimmer intake to pull in the piece of food? The one ripping the current past the skimmer or the one slowly plodding along?

I'd certainly rather pull mechanical chunks of organic waste out of my tank before they have a chance to break down and then become part of the chemical soup in the water.
While I see your view and get what you're trying to say two problems exist with your example. First a skimmer removes dissolved organics which I guess can be compared with food but we don't place organics/food in our overflow but rather rely on flow to get them there. So in real life that piece of food will get to the overflow faster if flow is higher, resulting in going to the sump sooner. Dissolved organics should be looked at differently than a food pellet, its concentration is distributed throughout the tank not in one particular location.

The second problem is the assumption less flow through the sump results in more water being filtered though the skimmer before going back to the display. First these are independent, the skimmer outputs the same as it takes in. So exactly how could one possibly determine how much overflow water is actually going in the skimmer and not simply bypassing it completely? With a lower turnover the amount of water being constantly recycled through the skimmer could actually be higher meaning less overflow water is going in compared to high turnover.

Regardless the point I'm making is that the two are completely independent. Dissolved organics are dissolved meaning the concentration throughout the tank will be virtually constant. The amount of organics taken in by a skimmer is essentially constant and independent from the water flow moving past it. High or low turnover (in limits), a standard in sump skimmer will work the same.

Lower sump flow rates are related to lower noise and less air bubbles but not skimmer performance. The only reading I've seen relating these two suggest higher flow rates as it will "keep solids in suspension, which increases feeding opportunities by fishes and invertebrates, and improves filter/skimmer opportunities to export such matter in a well-designed system"

Canadian
10-13-2009, 09:59 PM
A good skimmer removes both DOC and solid particulate. For instance I've had shrimp molts end up in my skimmer cup. I want my skimmer to remove as much solid particulate as possible before it becomes DOC - hence the reason for not having a filter sock that requires constant changing.

mr.wilson
10-13-2009, 10:07 PM
I agree with the idea that skimmers should be rated by bioload, but manufacturers are saddled with magic numbers that everyone in the hobby can understand. A better way to do it would be to measure water quality and compare it to a second sample taken 6 or 12 hours later. This would give you an index of decline and allow you to access how much equipment you need to keep it in check. Unfortunately that lowest common denominator is system volume not load. Some heavily stocked tanks are well balanced and subsequently put less demand on a protein skimmer. Other methods of nutrient export, chemical filtration and mechanical filtration also take the burden off of the protein skimmer. Protein skimming is limited to the removal of 80% of the available proteins and only 25% of the available TOC. For a proper evaluation of the abilities and limitations of protein skimming look here. http://www.advancedaquarist.com/2009/1/aafeature2

Protein skimmer design isn’t rocket science, but the only scientific formulas we have in determining size, contact time and bubble size are those offered by real life rocket scientist P.R. Escobal. His formulas have not been disputed to date and are summed up well in the following link http://www.hawkfish.org/snailman/skimmer101.htm

It is widely accepted that a two minute dwell/contact time is ideal for separating the maximum number of proteins and TOC (total organic carbon including both dissolved and particulate forms). This doesn't preclude the use of a protein skimmer that fits under your roof. In the case of a 400 gallon tank with a 1.33x flow through the protein skimmer, and a two minute dwell time, the contact chamber of the device needs to be 18 gallons. It sounds big, but so is a 400 gallon display tank, and you only need that size for optimum performance.

In addition to the comparatively low throughput rates recommended by Escobal (1.33 x per hour), protein skimmer manufacturers typically recommend 250-500 GPH throughput for larger units according to system volume and respective protein skimmer size. These specs typically equal 2 or 3 x the volume of the tank per hour and are chosen by practical trials rather than mathematical formulas. So why do some people disregard the recommendations of manufacturers and the formulas of rocket scientists in order to follow the 10x the volume of the tank guestimation of some kid working in an aquarium store?

The root of the 10x rule of thumb goes back to the days when we didn’t use closed loop pumps and we relied on a one pump system to keep detritus suspended (for feeding corals and collection in mechanical filters), to provide adequate gas exchange, and to deliver unprocessed water to filtration devices. There is no reason why we can’t pre-filter the water by collecting a thinner amount right at the surface air/water interface. This thin film is rich in surface-active agents (surfactants) that migrate to the air/water interface through the same process carried out in the protein skimmer. The practice of turning over large quantities of surface water draws a thicker intake from the display tank, thus diluting the hydrophobic (repelled by water) proteins we are trying to pre-filter.

The ideal system would collect a thin film of surfactants from the display tank and deliver it directly to the protein skimmer sitting in a sump (for safety/spillage reasons), after which it would be directed to the sump where the water can be further processed by a refugium, UV sterilizer, mechanical and chemical filtration methods, all of which requiring a similar slow throughput. The idea is to process all of the water thoroughly and only once before returning it to the display tank.

If your skimmer design doesn’t allow for a gravity feed, then the sump should be divided into two sections. One section holds the protein skimmer and the new unprocessed influent water, and the other holds water that has been processed by the protein skimmer reday fro further filtration and return to the display tank via a pump with the same output as the skimmer pump (less head loss). The water entering the first compartment by gravity or siphon from the display tank at the rate of “X”, can be pumped through the protein skimmer at the rate of “X” by a small feed pump. The processed water would exit the skimmer and enter the second compartment to assure it can only be filtered again after entering the display tank or in the case of the protein skimmer pump being greater than “X”. If the protein skimmer pump is less than “X” some water will bypass the protein skimmer, but the water will still only get processed once before returning to the display tank. The flow rate through the sump is directly related to the flow rate through the protein skimmer if you have an efficient first in first out (FIFO) plumbing system for your skimmer.

Refugiums, chemical reactors and UV units require the same type of flow volume so they can all be plumbed inline. In order to get a 99.9% kill ratio with a UV sterilizer, you can run no more than 4.16 gallons per hour per watt through it. In other words, a typical 30 watt UV unit should be fed no more than 125 GPH throughput, or the kill ratio will diminish accordingly. If you look at typical display tank and protein skimmer sizes you will find that the turnover ratios are about the same. Once again, P.R. Escobal’s formulas are considered to be the gold standard when sizing and establishing throughput for UV sterilizers. His UV formulas are summarized nicely here. http://www.aquariumadvice.com/articles/articles/44/1/Introduction-to-UV-sterilizers/Page1.html

The reason why you need to make sure your protein skimmer isn’t oversized is that you will have premature bubble popping which releases the bound proteins. As the bubble rises through the contact chamber it bombards the water passing in the opposing direction (down). The smaller the bubble, the more stable it is and the more likely it is to make it to the reaction chamber in the neck. Bubble stability increases as the bubbles bind hydrophobic proteins to form a skin. An oversized protein skimmer will cause premature bubble popping due to the lack of bubble stability. Proteins are both hydrophobic and hydrophilic (attracted to water) as they are polarized at each end. If the contact chamber is too large, the bound proteins will migrate back into the water.

Protein skimmers are primarily designed as chemical filtration, not mechanical. If you want to keep detritus, or a sinking food pellet suspended, it is the duty of a closed loop system, not the throughput. A throughput ratio of 10x will certainly not easily achieve this goal anyway.

The other benefits of following the scientific formulas and directly feeding protein skimmers is quieter overflows, no micro-bubbles and salt creep caused by oversized drains that lead to a sump compartment (ater goes directly to the skimmer where bubbles are welcome), less heat and noise from return pumps, better pod production in refugiums, a higher kill ratio for UV sterilizers, and better mechanical and chemical (longer dwell time) and mechanical (less bypass and breakdown) filtration.

The biggest problem in this hobby is the lack of effort hobbyists make to fine tune their existing equipment. Keep the glass on your lighting system clean, and spend less time "upgrading" bulbs. Use a smaller return pump and filter your water more thoroughly with fewer drain problems and better surface skimming. Plumb your skimmer right into your drain and get away from a "water mover" system that offers inefficient filtration.

sphelps
10-13-2009, 10:24 PM
A good skimmer removes both DOC and solid particulate. For instance I've had shrimp molts end up in my skimmer cup. I want my skimmer to remove as much solid particulate as possible before it becomes DOC - hence the reason for not having a filter sock that requires constant changing.
While this might happen from time to time I assure you protein skimmers work on a molecular level and are not effective at filtering out particles greater than a fraction of a millimeter. The fact that it collected such items is more of a coincidence than a function. It will also only filter particles that float or are basically neutrally buoyant. This will also likely cause more maintenance requirements to keep your skimmer clean and working efficiently. Skimmers will work better for longer with a mechanical pre-filter. Quite simply you're just justifying an omission.

sphelps
10-13-2009, 10:46 PM
Mr. Wilson, I'm slightly confused by your post and was hoping you could clarify.
First, only external/recirculating skimmers have an adjustable turn over rate and none are traditionally gravity fed, unless by gravity fed you simply mean with a pump because no skimmer should be run off gravity (such as straight from overflow) as it will never produce constant flow and cause the skimmer level to be either too high or too low. Also building a separate skimmer chamber which requires a pump to feed water out at the same rate of the skimmer is a new one for me, I have never seen this. The 10X turn over recommendation is based on tank/sump flow and not skimmer flow, I have never heard of someone running 10X tank turnover through a skimmer before. Today's skimmers are not co-current, air stone powered tall structures. They mostly use a single pump and do not offer flow control. Lastly sumps should be designed to handle the tanks/owners requirement for flow, this is fairly simple and eliminates things like mechanical filtration bypass and would provide adequate contact time for carbon.

lastlight
10-13-2009, 10:50 PM
Mr Wilson that was awesome. Thx for taking the time to share that.

pterfloth
10-13-2009, 11:03 PM
+1 Mr Wilson!

golf nut
10-14-2009, 03:10 AM
The slower the tank skims the more concentrated (read dirty) the water going to the sump is, the dirtier the water the more efficiently the skimmer functions.

banditpowdercoat
10-14-2009, 03:36 AM
But would that really mean the skimmer is more efficient, or working more efficient? or just theres more there to remove.

Like vacuuming a dirty 3 year old carpet compared to a 1 month old carpet? does it mean the vacuum is not working as efficiently on the newer carpet because its not pulling up as much junk?

golf nut
10-14-2009, 03:55 AM
Dan, if you wanted to remove a film of oil from the surface of a tank of water would you slowly add water to the tank so it comes off the surface slowly and gets caught in a sponge or would you pump it quickly.

mr.wilson
10-14-2009, 03:58 AM
only external/recirculating skimmers have an adjustable turn over rate
Absolutely, you cannot use the type of skimmer feeding that I am recommending with a one pump skimmer where the water feed and air production are produced with one pump. These protein skimmers are less efficient for that very reason. One pump skimmers still benefit from directing the effluent (processed) water to the return pump section of the sump as it allows new unprocessed waster to be pumped through. These types of skimmers function best if they are plumbed directly to the tank with no sump as they process water indiscriminately (no first in first out).

...and none are traditionally gravity fed, unless by gravity fed you simply mean with a pump because no skimmer should be run off gravity (such as straight from overflow) as it will never produce constant flow and cause the skimmer level to be either too high or too low.

The most efficient and quite drain from a surface skimmer is a siphon with an emergency overflow that has a constant slow trickle. There is no "toilet flush" siphon and siphon break with a constant siphon drain so the water level will be constant. A Durso or Stockman drain will also drain steadily if it is vented properly. The only instance that could cause a variation in the drain rate would be a toilet flush of an improperly vented drain. If "X" amount of water goes into a display tank, then "X" overflows at the same rate. The water level in the protein skimmer is regulated by the back pressure of a gate valve and or the height of the drain line.


Also building a separate skimmer chamber which requires a pump to feed water out at the same rate of the skimmer is a new one for me, I have never seen this.

It is a simple idea that greatly improves efficiency that is over-looked.

The 10X turn over recommendation is based on tank/sump flow and not skimmer flow, I have never heard of someone running 10X tank turnover through a skimmer before.

Tank flow rates are governed by closed loop pumps or less effective powerhead systems. Moving water to and from a sump does nothing for tank flow other than a side effect. The purpose of having a sump is to create a remote location to place filtration devices. Once you establish how many GPH these devices require, then you can pick a pump that does moves that much water. Anymore flow redundant at best, but more likely to decrease the efficiency of the filtration devices through a shorter dwell time and less concentrated surface skimming. Excessive, redundant turnover also causes noisy drains, salt creep, micro-bubbles, less surface tension at the overflow, and heat & electrical costs of an oversized pump.

Today's skimmers are not co-current, air stone powered tall structures. They mostly use a single pump and do not offer flow control.

You are correct, most skimmers these days are counter-current. The skimmers that were used in Escobal's work were also counter-current. Almost any protein skimmer can be plumbed for a closed loop (recirculating) pump for bubble production and a secondary feed for throughput of water. Protein skimmers with wood air diffusers introduce more air flow and with smaller bubbles than needlewheel, pinwheel, and venturi aspirated skimmers. The air-driven diffuser skimmer in the skimmer test I sited gave the same results as the downdraft and needlewheel skimmers in the test.

Lastly sumps should be designed to handle the tanks/owners requirement for flow

If you base the design on what you want, then stick with 10x turnover. If you want energy efficiency, better water quality, less noise and micro-bubbles, then size the return pump according to what the filtration requires to operate best.

this is fairly simple and eliminates things like mechanical filtration bypass and would provide adequate contact time for carbon.

No, delivering more water to the sump than the filtration devices require is not simple, it's more complicated and a waste of resources. The only bypass I would recommend is an emergency bypass for the protein skimmer feed incase something gets clogged, but I would have one in place with any drain system that doesn't have an emergency overflow. Todays standards are 20-40 x the volume of the tank in total flow. I go for quality over quantity, but even with the best flow dynamics, you won't achieve this with 10x the volume of the tank.

The worst scenario I come across is what I call a "water mover system". This is a sump with one or two poorly tuned or non-functional filters and lots of water coming and going from the display tank. A lot of resources are used to move the water, but little or no positive gain is achieved. Typically these systems have old carbon that is allowed to leach out any and all TOC (total organic carbon) it has absorbed, UV sterilizers that act only as heaters because the bulbs are expended or burnt out, protein skimmers that don't collect skimmate or sludge in the neck, and refugia that are allowed to overgrow and shadow the lower portions causing a slow unnoticed die-off.

mr.wilson
10-14-2009, 04:09 AM
Dan, if you wanted to remove a film of oil from the surface of a tank of water would you slowly add water to the tank so it comes off the surface slowly and gets caught in a sponge or would you pump it quickly.

The other way to test the theory is to take a small cup and quickly dip it into the tank, then do it again but this time submerge it a millimeter bellow the surface and you will see the surface tension isn't broken as much and water & oil is pulled from a thinner sample, over a greater surface area. You will see it pull water from several feet away.

Having a thin film overflow the surface skimmer will reduce the need for a coast to coast overflow. The best way to test the efficiency of an overflow is to place some flake food at one end of the tank and see if all of it either sinks or gets skimmed within 30 seconds. Any food that gets caught up in the middle, edges or corners means you have dead spots where films will accumulate. These oils are not only bad for water quality, they also diminish lighting intensity, and gas exchange.

banditpowdercoat
10-14-2009, 04:24 AM
My coast to coast, in conjunction with the OM 4 way, no dead spots on my waters surface :D

mr.wilson
10-14-2009, 04:33 AM
My coast to coast, in conjunction with the OM 4 way, no dead spots on my waters surface :D

Eliminating dead spots on the surface is another one of those details that makes a huge difference at no cost or compromise.

sphelps
10-14-2009, 04:28 PM
Good points and good information there Mr. Wilson. I agree that the best skimmer design is based on recirculating counter current but of course it is a simple option and not a requirement (just like everything else). Recirculating skimmers, on average, cost double and not everyone should consider modifying there skimmers, this is not a simple modification for most. Drilling the expensive acrylic body can often result in fracture and voided warranty.

I wouldn't personally ever setup a skimmer to be fed by a siphon over a pump, in theory the perfect siphon will deliver consistent flow but in practice it's not the case and if flow is suddenly increased a big mess will exist. But that doesn't mean it can't be done, I simply don't see the benefit and wouldn't recomend it, however everyone's thoughts are different.

Moving a lot of flow through the sump has many benefits, of course so does moving little flow. It's important to remember it's not a simple science and there are many ways to skin a cat. I won't go into too much of my reasoning again but I will say real experience and evidence trumps theory. I believe that the best resource for this can be found in the RC site where every month some of the worlds best tanks are showcased and described. There you will find almost all tanks showcased run return flows around 5-10x display volume, if not more. For me it's hard to argue with success, they got to be doing something right.

You're obviously a smart guy and you have experience in aquarium design but we definitely have some differences in opinion and what we consider simple, which of course is a good thing :wink:
I also noticed you're new to this site (WELCOME BTW :biggrin:), perhaps you could provide a link to your tank(s) or some of the work you've done. I always like to see the work of others who offer different approaches.

mr.wilson
10-14-2009, 05:15 PM
Drilling the expensive acrylic body can often result in fracture and voided warranty.

I know, most people would rather do their own dentistry than drill into a new protein skimmer :)

I wouldn't personally ever setup a skimmer to be fed by a siphon over a pump, in theory the perfect siphon will deliver consistent flow but in practice it's not the case and if flow is suddenly increased a big mess will exist.

Never say never. Technology and methodology is always adapting and evolving. If a sudden increase or decrease of flow ever occurred I would spin it as "intermittent wet skimmate to remove strongly hydrophilic proteins" :)

Moving a lot of flow through the sump has many benefits

Such as...

It's important to remember it's not a simple science and there are many ways to skin a cat. I won't go into too much of my reasoning again but I will say real experience and evidence trumps theory.

You haven't gone into any details other than "everyone else is doing it", and from my experience they are not all doing it. In my travels I see 3-5x the volume of the tank to be the common practice for return pumps. Apart from theory, in practice I use 3-5x the volume with a total tank flow rate of about 20x the total volume.

Dr. Stephen Spotte said it best "The successful maintenance of a seawater aquarium is mostly witchcraft mixed with a little science. In this book I have attempted to describe the science, but with the realization that understanding the witchcraft might be more useful."

Unless you care to share some of your witchcraft, we are stuck with my science :)

I believe that the best resource for this can be found in the RC site where every month some of the worlds best tanks are showcased and described.

I contribute regularly to RC threads, but I have never bothered to read more than one or two TOTM profiles. I don't find them to be completely honest or particularly reflective.

There you will find almost all tanks showcased run return flows around 5-10x display volume, if not more. For me it's hard to argue with success, they got to be doing something right.

There is no cause and effect of what you are claiming. If sure most of the tanks were glass rather than acrylic and used metallic pumps rather than magnet coupled ones, but this doesn't offer empirical evidence of anything. If you look at the TOTM historically you will see an evolution of technology and methodology. To deny this is to deny progress, and that is what I see with your opinion.

You're obviously a smart guy and you have experience in aquarium design but we definitely have some differences in opinion and what we consider simple, which of course is a good thing :wink:

I'm more experienced than smart, but I'm getting there. I have the advantage of 30 years of mistakes to learn from. I'm done making most of them :)

I also noticed you're new to this site (WELCOME BTW :biggrin:), perhaps you could provide a link to your tank(s) or some of the work you've done. I always like to see the work of others who offer different approaches.

I'm active on a few sites, so I decided to divert some of my time over to this forum. This forum seems more active than the other Canadian site I belong to that I won't mention :)

I don't expect anyone to do a 180 and follow my advice, and what I said last year was as different from today as today's will be from next year's. I participate on these forums to learn and share what I have learned. I get inspiration from others and new insight into old questions.

I didn't come here to pick a fight, but it looks like I landed in the middle of one. Don't take anything I have said personally. It's all in good fun.

Parker
10-14-2009, 06:26 PM
I've enjoyed the back and forth banter, I've learned a lot.

I think its safe to say there is limitless ways of doing things and limitless reasons for doing them. Once you throw a human into the equation math and science can go right out the window. I know I've made some choices based on ascetics rather then what might be considered best practice.

sphelps
10-14-2009, 06:29 PM
I know, most people would rather do their own dentistry than drill into a new protein skimmer :)
And for good reason, quite often skimmer bodies are very thin to cut down on costs and acrylic can become more brittle from extended use.

Never say never. Technology and methodology is always adapting and evolving. If a sudden increase or decrease of flow ever occurred I would spin it as "intermittent wet skimmate to remove strongly hydrophilic proteins" :)
Interesting but I see fish poop on the floor as simply fish poop on the floor. External skimmers can make a big mess which is why I see a pump as a clear advantage.

Such as...
Well this thread is about skimmers and another discussion regarding turnover flow is currently taking place in another thread, I didn't want to be too repetitive but...
http://canreef.com/vbulletin/showpost.php?p=453474&postcount=15
Basically I think it's fairly obvious that more return flow means more filtration. A sump is essentially a filter, bigger filters with more flow, filter more water quicker. A typical skimmer is independent from return flow and will essentially work the same regardless of return flow (in limits). Eliminating or reducing the need for additional power heads or closed loops is also a big plus in my book and I believe it results in a simpler system. You can increase in tank flow all you want but if you're limited by return flow your filter is also limited, higher return flow will not only keep particles and matter suspended but it will also filter them out faster. Not everything rises perfectly to the top of a tank and gets filtered out through the overflow in real life. Surface skimming is always going to be limited by blocks we install to prevent creatures from escaping and high total tank flow keeps things mixed up. I've also seen surface skum build up problems with lower flow tanks.

You haven't gone into any details other than "everyone else is doing it", and from my experience they are not all doing it. In my travels I see 3-5x the volume of the tank to be the common practice for return pumps. Apart from theory, in practice I use 3-5x the volume with a total tank flow rate of about 20x the total volume.

Dr. Stephen Spotte said it best "The successful maintenance of a seawater aquarium is mostly witchcraft mixed with a little science. In this book I have attempted to describe the science, but with the realization that understanding the witchcraft might be more useful."

Unless you care to share some of your witchcraft, we are stuck with my science :)
Well your science isn't that scientific, it's really just an opinion based on your own experiences and some information from various sources, just like mine.
To me turnover means the flow turned through the sump. Pure closed loop, in tank flow doesn't really turnover anything. I prefer to practice around 10x turnover with additional in tank flow if required, many times this is not required as tank demands are based on coral species kept. I've gone into as much detail as you have on this subject, perhaps it's split between two threads but it is there. The problem is it doesn't really mean anything without evidence to back it up which is why I for one look at other peoples experiences as well rather than being blinded by my own.

I contribute regularly to RC threads, but I have never bothered to read more than one or two TOTM profiles. I don't find them to be completely honest or particularly reflective.
Well I for one do enjoy reading TOTM profiles, I think it's interesting to see what successful tanks use for equipment and I think a lot can be learned from other peoples experiences. Taking ideas from a group will almost always produce better results than taking ideas from one individual. I'm not sure why you would consider such a thing dishonest, perhaps the parameters aren't always that accurate but the equipment and healthy corals looks awfully real to me.

There is no cause and effect of what you are claiming. If sure most of the tanks were glass rather than acrylic and used metallic pumps rather than magnet coupled ones, but this doesn't offer empirical evidence of anything. If you look at the TOTM historically you will see an evolution of technology and methodology. To deny this is to deny progress, and that is what I see with your opinion.
Why on earth would I deny that, of course progress exists. There's obviously more involved in these tanks but the maintainers of such aquariums seem to know what they're doing, if you want to believe it's just all luck and witchcraft that's your call.

I'm more experienced than smart, but I'm getting there. I have the advantage of 30 years of mistakes to learn from. I'm done making most of them :)
Well I guess we're opposites which is probably why we get along so well :wink:, I consider myself smarter than I am experienced. I have an engineering degree and I believe I pick up things faster than most people. Where I lack personal experience I have to rely on other peoples experience to fill gaps when necessary.

I'm active on a few sites, so I decided to divert some of my time over to this forum. This forum seems more active than the other Canadian site I belong to that I won't mention :)

I don't expect anyone to do a 180 and follow my advice, and what I said last year was as different from today as today's will be from next year's. I participate on these forums to learn and share what I have learned. I get inspiration from others and new insight into old questions.

I didn't come here to pick a fight, but it looks like I landed in the middle of one. Don't take anything I have said personally. It's all in good fun.
I usually don't take things personally unless it's obvious it's meant to be. I've enjoyed our discussion so far and I'm here for the same reasons you are.
Cheers

sphelps
10-14-2009, 06:58 PM
I've enjoyed the back and forth banter, I've learned a lot.

I think its safe to say there is limitless ways of doing things and limitless reasons for doing them. Once you throw a human into the equation math and science can go right out the window. I know I've made some choices based on ascetics rather then what might be considered best practice.

Would definitely agree, reef tanks are more of an art form than a science. The science is the easy part but making it all come together is what makes or breaks a tank.

mr.wilson
10-15-2009, 01:32 AM
External skimmers can make a big mess which is why I see a pump as a clear advantage.

I don't know what you mean by "external skimmers". I assume it's a type of protein skimmer and not a surface skimmer.

Basically I think it's fairly obvious that more return flow means more filtration. A sump is essentially a filter, bigger filters with more flow, filter more water quicker.

I see sumps as a drip catcher for filtration devices, not as filters in and of themselves. Sometimes less is more. You never gave any reasoning or linked any sources for the 10x turnover you feel so strongly about. Why not 40x if you want to do it all with one pump? That way your drain will not need to be vented and you wont get the salt spray and suction sound. There has to be reasoning why a particular turnover volume achieves a dynamic equilibrium.

A typical skimmer is independent from return flow and will essentially work the same regardless of return flow (in limits).

Very few if any protein skimmers cannot be operated on a two compartment FIFO system as I have described above. Even a becket skimmer with a high volume pump can be plumbed with the effluent line directed to a second compartment so skimmer treats new water first.

If you compare two scenarios with the first one delivering 2500 GPH to the sump drawn over a 12" x 6" overflow, then a second system where only 1000 GPH was drawn over the same overflow and delivered to a sump. The second scenario would have a higher concentration of surfactants due to a thinner film collected at the surface. It's the same argument one would make for a longer overflow box or removing the teeth from an overflow. Both scenarios keep the protein skimmer fed with fresh water. The first version moves some extra water that doesn't reach the protein skimmer. If you don't use a FIFO method, the 2500 GPH system will process the same water over and over with greatly diminished efficiency.

There are many ways to skim the cat, but you must use a method that assures that the protein skimmer is fed pre-skimmed (highly concentrated/protein-rich water) and skim it only once before returning it to the tank where it mixes with unfiltered water.

Eliminating or reducing the need for additional power heads or closed loops is also a big plus in my book and I believe it results in a simpler system. You can increase in tank flow all you want but if you're limited by return flow your filter is also limited, higher return flow will not only keep particles and matter suspended but it will also filter them out faster.

If your gola is to eliminate closed lops and power heads than you will need a 20x turnover rate, providing your flow dynamics are good, and they will be limited by only surface draining.

Not everything rises perfectly to the top of a tank and gets filtered out through the overflow in real life. Surface skimming is always going to be limited by blocks we install to prevent creatures from escaping and high total tank flow keeps things mixed up. I've also seen surface skum build up problems with lower flow tanks.

I wouldn't use teeth on an overflow for this reason. Horizontal barriers placed parallel to the overflow (above it) will keep out fish and inverts without breaking surface tension or reducing overflow surface area. Plastic gutter guard placed vertically inside an overflow box will serve the same purpose.

This is where a closed loop system offers superior flow dynamics. A return and intake can work together to build up inertia (kinetic energy). Closed loop intakes can be located in areas where detritus settles and inline mechanical filters can be used to collect it. Closed loops also offer a back-up system for flow (gas exchange) if sumps run dry, pump failure, or while you are servicing the filtration in the sump or feeding.

Using a one pump system with a 10x turnover ratio will not adequately keep detritus suspended, create ripples on the surface, keep the whole surface moving, and reach all parts of the reef structure.

Well your science isn't that scientific, it's really just an opinion based on your own experiences and some information from various sources, just like mine.

It isn't really my science, I quoted a number of very reputable sources and I showed the math. You didn't explain your experiences and you didn't show the math or even a link to the source of your magic number of 10x turnover. If you need me to back up anything I have said with scientific information than I will be happy to. I am also willing to listen if you can find fault with any of the specifics of my logic.

To me turnover means the flow turned through the sump. Pure closed loop, in tank flow doesn't really turnover anything. I prefer to practice around 10x turnover with additional in tank flow if required, many times this is not required as tank demands are based on coral species kept. I've gone into as much detail as you have on this subject, perhaps it's split between two threads but it is there. The problem is it doesn't really mean anything without evidence to back it up which is why I for one look at other peoples experiences as well rather than being blinded by my own.

The point her is simple. Why do you move water to and from your sump? The purpose is to give the filtration devices unprocessed water to clean. If your devices operate best at 3-5x the flow of the tank, then the other 5-7x you are moving is simply a juggling act. If our goal is to use our resources wisely, then we need to put more thought into magic numbers.

I appreciate that you have found this 10x formula to work best for you, but you don't have me convinced that you have had less success with 3-5x turnover or with a closed loop system (greater than 10x).

Well I for one do enjoy reading TOTM profiles, I think it's interesting to see what successful tanks use for equipment and I think a lot can be learned from other peoples experiences. Taking ideas from a group will almost always produce better results than taking ideas from one individual. I'm not sure why you would consider such a thing dishonest, perhaps the parameters aren't always that accurate but the equipment and healthy corals looks awfully real to me.

I treat TOTM's the same way I treat a show & shine car show. It's nice to see success and a well groomed finished product, but I prefer to follow the learning curve as the transmission comes out and you pass around the greasy factory manual as you come up with innovative modifications. I learn more from forum discussions about what does and doesn't work. I learn more from failures than triumphs, but it doesn't stop me from enjoying a mint TR6 :)

Well I guess we're opposites which is probably why we get along so well :wink:, I consider myself smarter than I am experienced. I have an engineering degree and I believe I pick up things faster than most people. Where I lack personal experience I have to rely on other peoples experience to fill gaps when necessary.

I would have gone easier on you if I had known you had an engineering degree working against you :)

I'm not asking you to explain the logic behind a 10x turnover ratio just to be a smart ass. I would like nothing more than to be proven wrong and learn something new. Heated debates on forums are my only chance to win an argument. I don't stand a chance with a debate with my wife :)

mr.wilson
10-15-2009, 02:09 AM
sphelps: I forgot to answer a question you asked earlier about posting my aquarium. I don't have one going right now, but I will be doing one in the January/February. I work in the aquarium industry, but mods frown on commercial posts so I don't post any pictures of my work unless they pertain to a specific question someone is asking.

sphelps
10-15-2009, 08:54 PM
I’m not quoting anything from previous posts because it’s starting to turn into meaningless debates and arguments. Simply quoting selective parts of a statement and arguing only with those parts is fairly meaningless and doesn’t present any new information but rather disagreements.

An external protein skimmer is a protein skimmer that works externally (not in sump). When someone refers to “recalculating protein skimmers” for the most part these skimmers are external models. In sump models are not usually recirculating unless modified by the owner.

Really the 10x flow rate rule is common knowledge; many basic guides to saltwater aquariums will state a total flow rate of 10 times the tank volume is a good rule of thumb. My way of thinking is to start with the minimum requirement, which I believe is about 10x, then supplement more if needed and of course only if it’s practical. Remember I’m not arguing the fact that 3-5x won’t work but rather than running 10x will also work, personally I believe it may work slightly better but that’s not my main argument. If a tank was small enough and it did require 40x turnover a single pump system could be very practical. For example if you had a 20 gallon aquarium you could push 800gph through the overflow if you wanted, it would be better in my mind than putting power heads in which would just clutter up a small tank. However I would never see the need to run that much turnover in most tanks, especially smaller ones and of course it’s simply not practical to use a single pump to push 4000gph in a 100gallon tank.
As requested:
“As with any complex subject in this hobby, people are always looking for (and giving) rules of thumb. With regard to water movement in reef aquariums, many authors will advocate at least 10 times the volume of the aquarium per hour. So if you have a 100-gallon reef, you should be moving around 1000 gallons/hour. This is a fine starting point as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium.”
http://www.advancedaquarist.com/issues/april2003/beginner.htm

I love how the term dynamic equilibrium was mentioned because in my mind it hasn’t really been considered. One theory states that with lower return flow you’re going to end up with a higher concentration of organics in the sump however this would only be true for the beginning of the cycle and if a build up exists. Once steady state is reached a tank shouldn’t have a build up of dissolved organics, the skimmer should have already taken them out and continues to do so as more are added. Now the other approach is higher flow but less concentrated so at the beginning of the cycle it may take longer to remove built up organics but once steady state is reached the results would be the same. I’ll try and explain this again in another way; if you have two skimmers and one that takes in a higher concentration of organics but these organics are supplied at a slower rate and the second skimmer takes in less concentration however it’s supplied at a faster rate. Once equilibrium is reached the results will be the same. A skimmer will only filter out a certain percentage of organics anyway and at the end of the day no matter what the flow rate through the sump a skimmer will eventually turn over all the water eventually either way. So on one hand we have a lower flow rate that could possibly have a higher concentration but takes longer to turnover the tanks volume and on the other hand we have a higher flow rate which could possibly have a lower concentration but turns over the tank volume faster. The way I see it, these are the same at equilibrium. It’s like walking a shorter distance compared to driving a longer distance; the question is what are the speeds and distances and which one is faster.

The last thing I’ll note on this is in regards to this so called higher concentration, is that this is not something I really buy and would be very difficult to prove either way. A lower flow rate may take a thinner layer and if there was a build up of organics the concentration would be greater however at steady state there wouldn’t be a build up, otherwise you would need a new skimmer. In addition while it may be true that organics rise that doesn’t mean all the dissolved organics are located at the very surface of the water. On top of that you’ve got tremendous amount water flow in the display so it’s not really realistic to say you’ll see a higher concentration of organics at the surface of the water. As long as you have surface skimming you shouldn’t see a build up over at steady state. This is especially true for dissolved organics, since you know, they are dissolved.

I understand the FIFO method approach but it can’t actually be pulled off. Even with a 3 times turnover on a 100g tank you’re taking about 300gph which is too much for a recalculating skimmer and any other skimmer (made for 100g tank) that pulls in that much water isn’t going to skim out 100% of the organics anyway so no matter what you going to get bypass, and then going back to equilibrium as described above you’ll end with the same results regardless.

I’m not sure what is meant by horizontal barriers so I can’t comment on how effective they are unless an example is provided but I know placing netting inside the overflow may prevent creatures from entering the sump but could still result in death, more than likely they will be stuck on the net and not be able to return to the tank on there own. It’s very simple to come up with a solution for anything and everything but if it’s not practical it’s not a real solution. Most tanks use a vertical guard on the overflow that disrupts surface skimming for obvious reasons.

While closed loops have advantages, again they are not always practical. A closed loop and inline mechanical filters will add complications most aquarists would prefer to avoid. Also closed loops are not much more efficient at creating flow as a return pump because the majority of head loss results from plumbing. Most aquarists would prefer power heads on most tanks; they are easier to maintain, easier to install, more efficient, and provide substantially more options for flow dynamics. With a good turnover rate and added “kinetic energy” :rolleyes: (which btw is related more to velocity than flow rate) from power heads you can filter out sufficient particulate matter without the use of complicated closed loops and mechanical filtration. Remember less is more ;)
Also in regards to efficiency this can be approached many ways however I will use my tank as an example. I run a return pump and two tunze power heads, if I drop a size in return pump I’ll save 17W and loose over 500gph, if I make that up with another power head how am I saving power? I’ll actually be using about the same but I’ve added more clutter, complication and maintenance to my tank. As stated my tank uses one return pump and two power heads, the return pump puts out about 1000gph with head and is rated at 65W (although I’m sure it’s using significantly less power) and my tunzes pulse so I’ll assume an average of 3000gph at 45W combined. That’s 110W or less for a 40X turnover on a 100 gallon tank. I’d like to see less power used and better flow on the same size tank using a smaller return pump and a closed loop. But I certainly wouldn’t want to see what it looks like.

I’m not looking for math or sources to back up claims, mainly because I don’t care that much but also because I’m not disagreeing. I know may people just love to argue but that’s not my goal here. Honestly you can use pretty much whatever flow you want for a sump turnover and my argument is that it doesn’t matter. Yes lower turnover rates are quieter and for this reason more common because higher flow rates require more experience to achieve quieter results. In addition lower flow rates require cheaper internal pumps; high flow pumps are more expensive and for the most part louder.

The two main arguments aren’t really that different, one argument is for 5x and the other is for 10x, however my argument isn’t really an argument. I’m not set in my ways but rather I believe advantages and disadvantages exist for both but really we’re not talking about a huge difference here. I’m going to say something and I honestly hope it doesn’t offend anyone but from my limited experience in both this hobby and my career, I have found that too much experience can be a bad thing. The main reason relates to the old saying, you can’t teach an old dog new tricks. This holds true in many cases, lots of guys I work/deal with are extremely reluctant to change and are set in there ways. Not that their ways are necessary bad but sometimes advancement and technology provides new opportunities and methods worth trying. For example how long have people been using the Herbie style overflow? Before this style of overflow it was virtually impossible to create quiet and bubble free high flow returns so nobody did it.

I’ve said it over and over again and feel now that I’m really beating it too death but a flow rate of 3-5x will produce success and so will 10-15x there really isn’t much of a difference. Skimmers are independent and other parts of the sump filtration need to be designed for a certain flow rate. What that flow rate is, is completely up to the owner’s or maintainer’s preference and there is no real scientific evidence to support either option.


Mr. Wilson, the way you compare TOTM to show n shines is completely irrational in my books. You can fake a car; it can be really nice but not work at all. Also they really only go together in one way until you get into customizing but the same rules apply. You can’t really fake success with a marine tank, you can clean it up a little but in the end you can’t fake it. In fact most will always say it looks better in person. Why do so many people now love using T5 lighting? I can guarantee you it’s because of all those beautiful European tanks. It doesn’t mean you’re guaranteed success and the same results by using them but it sure as heck shows they work. That’s my point with TOTM, sure nothing guarantees anything but if almost all successful tanks use something it probably works pretty good or at least you can’t say it doesn’t work.

Also I did see your webpage but was hoping to see something with a little less fluff. Not trying to prove anything but I was hoping to see examples of the filtration techniques you exercise and the mature tanks that prosper from it. I only ask out of curiosity as some of your techniques both scare and fascinate me. I can guarantee that Mods won’t object to you posting some pictures of your previous tanks, whether you owned them or not it wouldn’t be considered advertisement. Plus I’m sure after 30 years you’ve owned your fair share of aquariums.

golf nut
10-16-2009, 12:31 AM
I am not sure if you noticed, but if you continue to read the article from the magazine you quoted you will see the following, if you read further you might find that the writer is actually advocating against 10x through the sump rather 3x or 4x is better..

As with any complex subject in this hobby, people are always looking for (and giving) rules of thumb. With regard to water movement in reef aquariums, many authors will advocate at least 10 times the volume of the aquarium per hour. So if you have a 100-gallon reef, you should be moving around 1000 gallons/hour. This is a fine starting point as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium.
Many reef aquarists use some sort of overflow in the tank to take water to an external container called a sump. In the sump various tools such as protein skimmers, carbon containers, reactors, etc. filter the water. The water is then returned to the aquarium. This is referred to as an open loop. The volume of water that flows through this loop need only be 3-4 times the volume of the tank (not 10+). This is the filtration flow rate. The rule of thumb that was mentioned earlier refers to the circulation rate in the aquarium. This number takes into account, not only the return from the filter, but circulation from various other pumps as well. I cannot tell you how many times people have come to me and asked how they can quiet there filter down on their 90 gallon tank because they are trying to put 900 gallons/hr through their overflow.
http://www.advancedaquarist.com/issu...3/beginner.htm

sphelps
10-16-2009, 12:53 AM
I am not sure if you noticed, but if you continue to read the article from the magazine you quoted you will see the following, if you read further you might find that the writer is actually advocating against 10x through the sump rather 3x or 4x is better..
Yes I did notice, did you notice the reasoning (noise not performance) and the fact it has nothing to do with my argument or why I quoted that? Like I said before some just love to argue but I didn't say 3-5x was wrong just that it's not a requirement and 10x will work equally well if you can deal with the higher flow. Also note the date of the article.

golf nut
10-16-2009, 01:00 AM
Yes I did notice, did you notice the reasoning (noise not performance) and the fact it has nothing to do with my argument or why I quoted that? Like I said before some just love to argue but I didn't say 3-5x was wrong just that it's not a requirement and 10x will work equally well if you can deal with the higher flow. Also note the date of the article.
You appear to be confirming your 10x turnover sump rate theory, however the article simply claims that 3x is adequate, otherwise they would have advocated a 10x capacity and explained how to select the correct size pipe for a silent overflow

sphelps
10-16-2009, 01:08 AM
You appear to be confirming your 10x turnover sump rate theory, however the article simply claims that 3x is adequate, otherwise they would have advocated a 10x capacity and explained how to select the correct size pipe for a silent overflow
Like I already stated, it takes more experience to run higher flows through overflows properly, it's not for everyone and it's not necessarily better than lower flow. That article is for beginners, which you would have noticed if you read the title rather than immediately trying to find something to argue with. I would never tell a beginner to use 10x turnover just like I wouldn't tell one to use a herbie overflow either.

golf nut
10-16-2009, 01:16 AM
You quoted the article to back up your statement, I am arguing no more than you are.

I have always promoted low flow, and have used syphon systems for many years, I have never advocated a Durso, a Durso is for people that have incorrectly sized their drains.

Please refrain from accusing me of making this a personal issue.

sphelps
10-16-2009, 01:32 AM
You quoted the article to back up your statement, I am arguing no more than you are.

I have always promoted low flow, and have used syphon systems for many years, I have never advocated a Durso, a Durso is for people that have incorrectly sized their drains.

Please refrain from accusing me of making this a personal issue.
Perhaps you could read things properly before making your arguments, if you did you would realize that quote had very little to do with my points. It was only intended to show that 10x is a general rule of thumb for total flow, nothing more.

golf nut
10-16-2009, 01:37 AM
Perhaps you could read things properly before making your arguments, if you did you would realize that quote had very little to do with my points. It was only intended to show that 10x is a general rule of thumb for total flow, nothing more.

What has 10x total flow got to do with 10x sump rates? they ask for 3x sump rates and 10x total flow, not your 10x sump recommendation, trust me I read it properly, I think you were the one that used it to prove your point, but had not read it properly.

sphelps
10-16-2009, 01:55 AM
What has 10x total flow got to do with 10x sump rates? they ask for 3x sump rates and 10x total flow, not your 10x sump recommendation, trust me I read it properly, I think you were the one that used it to prove your point, but had not read it properly.
Interesting, did you notice that repeatably mentioned the 10x flow is general guideline tank flow but obviously some tanks require more. I just think it's easier to run 10x through the sump and then add extra if it's needed with power heads. I also mentioned time after time that I'm not arguing for 10x sump turnover nor am I recommending it. My point has always been that people have options, and just because some choose to produce there tank flow differently than others doesn't mean they are wrong.

I never took a side and said what was wrong and what was right. Simply put, people think differently and have different priorities, low flow or high flow, it makes little difference.

golf nut
10-16-2009, 02:08 AM
I never took a side and said what was wrong and what was right. Simply put, people think differently and have different priorities, low flow or high flow, it makes little difference.

Unfortunately if you had made this statement 50 posts ago we wouldn't be still posting back and forth, the fact is in general you feel 10x is the acceptable rate and I believe the slower rate to be better and I will explain.

sphelps
10-16-2009, 02:18 AM
Unfortunately if you had made this statement 50 posts ago we wouldn't be still posting back and forth, the fact is in general you feel 10x is the acceptable rate and I believe the slower rate to be better and I will explain.

Really? I'm pretty sure I made it clear from the start, even in the thread this discussion started in.....

Like previously stated it's a matter of preference, both low and high flow have there advantages but it's a preference not a requirement. There are obviously limits but the range is large.

I never said low flow was a bad thing but rather advantages exist for both so it comes down to personal preference.


I’m not looking for math or sources to back up claims, mainly because I don’t care that much but also because I’m not disagreeing. I know many people just love to argue but that’s not my goal here. Honestly you can use pretty much whatever flow you want for a sump turnover and my argument is that it doesn’t matter. Yes lower turnover rates are quieter and for this reason more common because higher flow rates require more experience to achieve quieter results. In addition lower flow rates require cheaper internal pumps; high flow pumps are more expensive and for the most part louder.

I’ve said it over and over again and feel now that I’m really beating it too death but a flow rate of 3-5x will produce success and so will 10-15x there really isn’t much of a difference. Skimmers are independent and other parts of the sump filtration need to be designed for a certain flow rate. What that flow rate is, is completely up to the owner’s or maintainer’s preference and there is no real scientific evidence to support either option.

golf nut
10-16-2009, 03:04 AM
the fact is in general you feel 10x is the acceptable rate and I believe the slower rate to be better and I will explain.


Really? I'm pretty sure I made it clear from the start, even in the thread this discussion started in.....



Are you sure that's what you said? and that you were not biased for 10x sump returns?


The 10X turn over recommendation is based on tank/sump flow and not skimmer flow


Basically I think it's fairly obvious that more return flow means more filtration.


higher return flow will not only keep particles and matter suspended but it will also filter them out faster.


I prefer to practice around 10x turnover with additional in tank flow if required


My way of thinking is to start with the minimum requirement, which I believe is about 10x, then supplement more if needed and of course only if it’s practical. Remember I’m not arguing the fact that 3-5x won’t work but rather than running 10x will also work, personally I believe it may work slightly better but that’s not my main argument.


One more reason I see more being better is matching the flow doesn't actually make sense if you look at the numbers. My skimmer for example flows 4000L/h and it's rated for tanks up to 3000L, hmmm so the "required" flow results in a turn over of 1.3


I believe it's actually just over 10x

golf nut
10-16-2009, 03:25 AM
10x flow rates through sump..

Due to the large flow rate through the sump to the tank the water flowing through the overflow box creates it's own surface flow towards the overflow box, this is likely the original reason for such high return rates The issue with this method is that when only 2 or 3 x rates are required using 10x or greater pulls more than just the surfactants
from the tank but also a large percentage of non contaminated water which changes the surfactants properties from a concentrated to a diluted solution.

It causes drain issues which if understood could easily be resolved, it enhances micro bubbles in the sump, requires the need for a more expensive pump with high running costs.

Most if not all skimmer manufactures suggest it makes the skimmer less effective.





low flow rates through sump ie from 1x to 3x..

Providing flow is configured correctly the low flow rate will remove surfactants in concentrated form, it will make the skimmer more effective, reduce the need for large overflow systems,reduce the cost of the return pump, reduce the operating costs of the return pump, eliminate micro bubbles, reduce noise and heat.

sphelps
10-16-2009, 03:39 AM
Are you sure that's what you said? and that you were not biased for 10x sump returns?
Really? Are you serious? Most of those are even out of context and in the rest I even stated it's my preference or my belief or my opinion. I'm pretty sure I'm allowed to have a preference and the fact that my preference is around 10x was always made perfectly clear. Yes I provided some reasoning which focused on my preference because others had already covered reasoning for there preferences.

If we can't share our opinions, experience and ideas why are we hear? You actually took the time to search through all my posts and quote only the particular parts (out of context) for the sole purpose to prove me wrong and accuse me of saying something different. I'm sorry but I'm not going to feed your need to debate and argue anymore. Find someone else to stroke your ego.

mr.wilson
10-16-2009, 03:41 AM
I read the previous post you are talking about and I didn't see anything that you haven't said in this thread, so I agree we don't need to revisit it.

Everyone uses different terminology. I consider internal skimmers ones within the aquarium, which fell out of fashion 10 years ago. External skimmer is assumed, so I haven't heard the term in a long time. I locate external protein skimmers in sums to catch drips, overflows, and act as a fail-safe.

A 10x flow rate through the sump to be an industry standard or common knowledge. I did a search on Wet Web Media and the first article that came up was this one which recommends a 3-5x throughput. http://www.wetwebmedia.com/circrat.htm

I'm not arguing that a 10x throughput won't work, only that it is inefficient and a poor use of resources. An 800 GPH pump is suitable for a 200 gallon tank as a sump return. I don't agree that it would be a good choice for a 20 gallon tank.

Protein skimmers are limited to removing a maximum of 25% of the TOC so there will always be a buildup of dissolved organics that the protein skimmer cannot process. Your example of the two skimmers doesn't apply to our discussion of how much water to move through the sump. If you believe Escobal's theory that the proteins need a two minute dwell time for optimum bombardment time, then the skimmer with a more concentrated feed and longer dwell time will be more efficient than the second example you offered where less concentrated water is processed quicker. The two schools of thought are filter the water slowly and thoroughly, or quickly and less thoroughly. I agree there is an argument for either method, but the subject at hand is "do you move more water through a sump than the amount the protein skimmer will process?".

The secondary question is do you use a sump design that guarantees the skimmer processes the water only once before returning it to the display tank, or do you allow the skimmer to process the water numerous times while new unprocessed water bypasses it?

A higher volume turnover (10x) will cause the water passing over the overflow to crest higher. You will have around 1/2" of water skimmed from the surface. With half of that flow (5x) you will have 1/4" skimmed from the surface. The extra 1/4" collected with a larger pump will not move the surface water any faster, it will only dilute the surface film collected. Allowing half of that diluted water to bypass the protein skimmer due to an oversized return pump, coupled with a sump design that allows the water to be reprocessed over and over makes the system even less effective.

A horizontal barrier for an overflow is a piece of horizontal acrylic, eggcrate or glass that sits above the overflow edge perpendicular to it. It acts like a long slot rather than a series of small slots. It stops fish and inverts from getting through the same as vertical slots. Nothing gets trapped in the dry part of the overflow. The other way of draining without losing half of your surface area and breaking surface tension with teeth is to have a smooth overflow edge and place gutter guard mesh just inside the overflow box. As there isn't a gap, nothing will get stuck in the overflow and dry out.

There is no head loss with a closed loop even if you locate the pump in a basement because the intake is at the same height as the return. There is some friction loss if you use too many elbows, but Tigerflex hose minimizes it. Powerheads are a poor choice for added flow because they do not have adequately diffused intakes so they can injure livestock. They also cause heat transfer, vibrations, stray current, and poor flow dynamics. An external pump closed loop has a higher upfront cost but lower operational cost and more longevity (10-20 year pump life vs. 4-6 year pump life). The popularity of powerheads stems from low $50 increments needed to implement them. If you are on a budget, they get the job done without major drawbacks, but in the long run the cost more, require more maintenance and are less efficient.

Your current return pump RE65m3 (1717 GPH @ 65 watts) moves approximately 10x the volume of your display tank. If it was replaced with an RE25m3 (660 GPH @ 38 watts) it matches your skimmer pump which I estimate to be about 500GPH, and you would save 27 watts. Prop powerheads are not accurately rated for water movement so the flow rates the manufacturers offer, but let's assume they are accurate for the sake of discussion. You claim you are getting 3000 GPH @ 45 watts from the two powerheads combined. Using your numbers, you could add another powerhead for 22.5 watts and add 1500 GPH flow to make up for the 500 GPH you are dropping by matching the sump turnover rate with the protein skimmer intake. You would have a net gain of 1000 GPH flow with no bypass of the protein skimmer. There are numerous benefits for draining less water mentioned already.

A closed loop system offers the following benefits if executed properly...
1) Hidden influent and effluent lines.
2) Less heat transfer.
3) Less chance of stray electrical charge or shock hazard.
4) Less vibration.
5) No electrical cords in the water or running over the top of the tank.
6) Easy access to intake strainers.
7) More laminar and less turbulent flow for better inertia.
8) The ability to position flow anywhere in the tank.
9) Easy removal of pump if necessary.
10) True flow volume ratings.
11) High pressure flow.
12) Long pump life.
13) Only one cord to plug in.
14) Better circular flow.
15) The ability to locate the pump in a remote location (service area).

I make my technology and methodology decisions based on a thorough thought process, not based on my 30 years of experience in the hobby or 22 years experience in the aquarium industry :) In the 70's & 80's we used a 3x total flow rate for the display tank. In the 90's, a 10x flow rate became commonplace (likely the source of your information), and in recent years 20-40x has become the acceptable range. From my experience quality is better than quantity. If you use powerheads randomly aimed at the rock formation or front glass, you will need 40x flow to get the results you are looking for. If proper flow dynamics are implemented (circular flow, laminar flow, and up-flow for suspension) then you can get by with as low as 15x the volume of the tank for total flow.

The Herby method of draining was common in the 90's. It fell out of fashion after the Stockman and Durso modifications were introduced ten years ago. The problem with the Herbie method is it allows for a small drain point (one you can't even monitor) that can potentially clog. A safer system is a true siphon drain with a Stockman or Durso emergency drain.

I don't think you can fake a car in a car show or a tank in a TOTM. My point was a TOTM is a chance for everyone to see a nice tank that is successful, not a chance to follow the owners learning curve. You will see every possible method with good results. As a result, it's hard to measure their success and decide on the merits of the system. TOTM owners aren't required to explain or defend their methods. It's just raw data with a few anecdotes. I read a lot of books and articles and spend a lot of time on forms. I just don't have time to read a TOTM write up. I skimmed your tank build thread, but I would have read it if I was on this site as it played out. I guess news is more interesting than history to me :)

Europeans don't use T5 because it's better, but because it's cheaper. I lived in Europe for the last year and I can tell you from talking to hobbyists and industry people, MHL is preferred. T5 picked up some interest a few years ago, but they are waning in popularity now. Hydro rates are much higher in Europe, as is fuel. They all drive diesel over there (which I prefer) but they wish they could afford our gas guzzlers.

My clients look for aesthetics (or fluff as you call it), not fancy equipment or rare livestock. There is no point in putting filtration details on my website. I have lots of pictures posted on other forums (RC etc.). I prefer to modify cost effective filtration devices and lighting, rather than throwing money at overpriced equipment and haphazard configuration of it. I don't do maintenance or much in the way of stocking so I don't have many pictures of mature tanks.

mr.wilson
10-16-2009, 03:45 AM
“As with any complex subject in this hobby, people are always looking for (and giving) rules of thumb. With regard to water movement in reef aquariums, many authors will advocate at least 10 times the volume of the aquarium per hour. So if you have a 100-gallon reef, you should be moving around 1000 gallons/hour. This is a fine starting point as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium.”
http://www.advancedaquarist.com/issu...3/beginner.htm


You have quoted someone who is saying exactly what I am saying and counters your claim that 10x the volume of the tank needs to go to the sump whether it's needed or not.

"as long as you understand that this does not mean that you need to move 1000 gallons of water in and out of your aquarium" :question:

golf nut
10-16-2009, 03:49 AM
Really? Are you serious? Most of those are even out of context and in the rest I even stated it's my preference or my belief or my opinion. I'm pretty sure I'm allowed to have a preference and the fact that my preference is around 10x was always made perfectly clear. Yes I provided some reasoning which focused on my preference because others had already covered reasoning for there preferences.

If we can't share our opinions, experience and ideas why are we hear? You actually took the time to search through all my posts and quote only the particular parts (out of context) for the sole purpose to prove me wrong and accuse me of saying something different. I'm sorry but I'm not going to feed your need to debate and argue anymore. Find someone else to stroke your ego.

I simply quoted where you suggested that 10x was the magic number, not one of these quotes was out of context, the very fact that you disagree with me confirms the fact that you subcribe to higher than lower flow.

mr.wilson
10-16-2009, 04:09 AM
I will be the first to admit I enjoy playing the devils advocate. A debate or discussion doesn't have to be an argument. As long as you present your position with some substance you can't possibly be wrong, just different. There's also no reason why you have to follow my advice even if it is valid. I've used oversized, less efficient equipment just because it works out that way sometimes.

There are many contradictions in the reef hobby. I've run skimmerless tanks, tanks with no water changes, closed loop (pressurized) filtration systems, and experiments with every method that warranted the effort. Some work better than others, but they all work. I've done more than a few 180's, but I always admit it when I do it. I'm willing to take or at least consider advice from the bottom or top of the hobby.

You have the right to disregard information, but you can't dispute it with hollow claims for 50 posts then try to back peddle that you never said any of it.

I'm sure this thread has been interesting reading and a great soap opera for all that are following. Three people in the aquarium trade having a heated argument about a simple subject. Everyone is going to think it was staged :)

I think this particular horse is sufficiently flogged. If someone wants to discuss the merits of water changes in a new thread, I'm there. I'll even take "against" :)

Canadian
10-16-2009, 04:20 AM
A closed loop system offers the following benefits if executed properly...
1) Hidden influent and effluent lines.
2) Less heat transfer.
3) Less chance of stray electrical charge or shock hazard.
4) Less vibration.
5) No electrical cords in the water or running over the top of the tank.
6) Easy access to intake strainers.
7) More laminar and less turbulent flow for better inertia.
8) The ability to position flow anywhere in the tank.
9) Easy removal of pump if necessary.
10) True flow volume ratings.
11) High pressure flow.
12) Long pump life.
13) Only one cord to plug in.
14) Better circular flow.
15) The ability to locate the pump in a remote location (service area).


How about propeller pumps like Ecotech Vortechs or Tunze stream pumps? They address most of the cons of powerheads and consume significantly less power than a closed loop.

golf nut
10-16-2009, 04:27 AM
If someone wants to discuss the merits of water changes in a new thread, I'm there. I'll even take "against" :)
I would rather discuss the merits of not having teeth in an overflow box:)

golf nut
10-16-2009, 04:33 AM
How about propeller pumps like Ecotech Vortechs or Tunze stream pumps? They address most of the cons of powerheads and consume significantly less power than a closed loop.

This would make a great discussion.

hillegom
10-16-2009, 05:14 AM
Teeth not good? All the aquariums you buy with built in overflows that I have seen,have slots.

golf nut
10-16-2009, 05:27 AM
Teeth not good? All the aquariums you buy with built in overflows that I have seen,have slots.

Yes they do.. why?

hillegom
10-16-2009, 06:32 AM
I would rather discuss the merits of not having teeth in an overflow box:)

Because you imply that teeth are not good.
So I am wondering why are they not?

mr.wilson
10-16-2009, 06:32 AM
Teeth not good? All the aquariums you buy with built in overflows that I have seen,have slots.

Teeth reduce the surface area by 50%, so a 12" overflow is really a 6" overflow. As water passes the teeth the surface tension is broken so you don't skim a quick, thin layer from the surface, but rather more water is drawn from below the surface.

Overflows that have a return line or other flow interfere with the surface tension (flow directed near, or away from the overflow) near the overflow cause it to draw water from lower down. You can do a flake food test on some overflows and see water (& flakes) pulled into the overflow box from straight down. Return lines from the sump should be located at the surface at one end with the overflow box in the opposing end or corner (depending on aesthetics). Centre overflow boxes are less efficient and promote dead spots. Water should flow straight across the surface mixing with old water and flow directly into the overflow box taking with it anything on the surface. This system discourages back siphoning with the sump return and provides superior surface swirl and subsequent ripples if you have metal halide lighting.

Tanks typically come with teeth because aquarium manufacturers don't like change. A single slot is cheaper, stronger and easier to build, but tank manufacturers are slow to change. Most of them still use wet/dry filters oversized drains (allowing air and flushing issues) and one pump systems. In the case of a coast to coast style overflow, teeth make even less sense because the water depth at the edge isn't deep enough to attract fish to swim over it.

mr.wilson
10-16-2009, 07:07 AM
How about propeller pumps like Ecotech Vortechs or Tunze stream pumps? They address most of the cons of powerheads and consume significantly less power than a closed loop.

These pumps do solve most of the issues I mentioned, and they aren't a bad choice. Personally, I don't want to see any pumps or plumbing, but many people are concerned only about function and not about form.

They do use less power than any closed loop pump currently on the market, but the flow rates they have been designated are not the true values of the water they move. They also deliver volume and very little pressure. A pressure rated pump moves X amount of water plus all the other water it picks up and displaces as it travels across the tank. It's kind of a domino effect. If you were to add a dye to the effluent of the Vortech you would see less of it spread across the tank than what you would see with a typical closed loop pump.

Most of the closed loop effluents I use point up from the bottom to keep detritus suspended and to move dead water from lower regions to the air/water interface at the surface for gas exchange (oxygenation). Vortechs are only suitable for end to end flow, and they do it well.

Closed loop pumps draw in as much water as they put out. So do Vortechs, but the water intake doesn't have any impact on flow dynamics and flow is more turbulent (pumping into walls, rocks & opposing flow) than laminar (circular or rolling effect) without losing velocity due to friction or diffusion.

Typical powerhead set-ups direct water at the reef structure. This is not how it works on natural reefs. Water should change direction to offer suspended food from all angles. Good flow creates a snow globe effect. Chaotic flow with poorly placed powerheads drives detritus into reef structures and the sand bed.

A Sequence Dart pump uses 135 watts, and I pay $0.11 per Kw/h in Toronto including all of the extraneous charges. That comes to less than $11 per month if it runs 24hrs a day. If you can find a more efficient pump that truly moves the same amount of water (3600GPH) at half the wattage then you save $5.50 per month. A savings is a savings, but $5.00 isn't enough to tip the scale much.

I don't have much experience with prop powerheads like the Vortech but they look like they will claim the occasional invert or fish. They also require regular cleaning that you don't need with closed loop systems.

I find that drilling out rocks with a diamond bit or covering PVC ports with concrete or epoxy & aragonite makes them invisible in the tank. I'm trying to get away from swiss cheese tanks with multiple holes to keep costs and liability down. As long as you hide the pipes there's nothing wrong with running them over the top of the tank. You trim $1000 off of the cost of a big tank (no tempering or hole charges), production time is cut in half, and you save on bulkhead and valve costs. This brings the cost down to less than a comparable system with powerheads.

Canadian
10-16-2009, 02:53 PM
They do use less power than any closed loop pump currently on the market, but the flow rates they have been designated are not the true values of the water they move.

Absolutely not true. In fact one of the pumps was recently scruitinized by Dana Riddle and found to move MORE water than the manufacturers claims:
http://www.advancedaquarist.com/2009/10/review


Most of the closed loop effluents I use point up from the bottom to keep detritus suspended and to move dead water from lower regions to the air/water interface at the surface for gas exchange (oxygenation). Vortechs are only suitable for end to end flow, and they do it well.

Again, not true. The pickup from my little Vortech MP20 draws detritus up from the bottom of the tank 14" beneath it to keep it suspended in the water column

Closed loop pumps draw in as much water as they put out. So do Vortechs, but the water intake doesn't have any impact on flow dynamics and flow is more turbulent (pumping into walls, rocks & opposing flow) than laminar (circular or rolling effect) without losing velocity due to friction or diffusion.

See above - not true.

Typical powerhead set-ups direct water at the reef structure. This is not how it works on natural reefs. Water should change direction to offer suspended food from all angles. Good flow creates a snow globe effect. Chaotic flow with poorly placed powerheads drives detritus into reef structures and the sand bed.

Strawman argument. Poorly directed and placed closed loop outlets do likewise. Your argument here is simply a function of poor application and has absolutely nothing to do with the inherent qualities of either a prop pump or closed loop.

A Sequence Dart pump uses 135 watts, and I pay $0.11 per Kw/h in Toronto including all of the extraneous charges. That comes to less than $11 per month if it runs 24hrs a day. If you can find a more efficient pump that truly moves the same amount of water (3600GPH) at half the wattage then you save $5.50 per month. A savings is a savings, but $5.00 isn't enough to tip the scale much.

And that 100+ watts difference in heat produced is pumped back into the room and eventually requires more hydro consumption in the form of increased work for the chiller, AC, fan to remove to keep temperatures down. Now you've probably doubled your savings to around $120 a year - I'll take that $120 in savings and go buy some pretty new frags.

They also require regular cleaning that you don't need with closed loop systems.

Just like you have to clean the impeller on a closed loop pump to remove eventual precipitation so too do you clean up the propeller on a prop pump - no difference in maintenance here.

golf nut
10-16-2009, 04:59 PM
We are not really talking apples to apples here, both vortech and tunze claim flow numbers that becomes converted to gallons per hour of flow.
I would not argue their claims in the slightest, but just for a second could you answer me one simple question, if a vortech or tunze produce 3000- gph of flow , and you throttle back a dart to produce 3000 gph would the result be the same?

sphelps
10-16-2009, 05:17 PM
There is no head loss with a closed loop even if you locate the pump in a basement because the intake is at the same height as the return. There is some friction loss if you use too many elbows, but Tigerflex hose minimizes it. Powerheads are a poor choice for added flow because they do not have adequately diffused intakes so they can injure livestock. They also cause heat transfer, vibrations, stray current, and poor flow dynamics. An external pump closed loop has a higher upfront cost but lower operational cost and more longevity (10-20 year pump life vs. 4-6 year pump life). The popularity of powerheads stems from low $50 increments needed to implement them. If you are on a budget, they get the job done without major drawbacks, but in the long run the cost more, require more maintenance and are less efficient.

Comments like this make me question your design experience, while I wouldn't expect most hobbyists to understand pipe dynamics I would expect an experienced designer to understand some basics regarding flow mechanics in piping systems. Static head is only one part of head loss and even with correct pipe sizes and flexible pipe friction losses are large and plumbing the pump into the basement would add huge losses from friction. You can never completely avoid elbows, tees, unions, and ball valves. These all add significant losses. In addition adding systems to rotate flow will also add significant losses. But your major losses will always come from pipe length and over time your roughness factor increases adding more friction to the system.

On the average return plumbing friction losses will usually add about the same head pressure as the static head. For example, with proper pipe sizing, if you have 4 feet of static head your total head loss will be around 8 feet total. Closed loops always have more plumbing than returns, more outputs and more elbows. In one of my previous setups I used two dart pumps, one on the return the other on a closed loop which used an 4way OM with four outputs. I got more flow through my return than through my closed loop and the maintenance required to keep it working properly and the added complication and noise was enough to prevent me from doing a similar system.

A good power head like a controllable tunze or vortec is a far superior option. They can be controlled by microprocessors and tuned to a frequency that matches your tank dimensions resulting in maximum water movement with minimal power consumption. The flow control is electronic which allows for unlimited possibilities for both flow control and dynamics. To say a closed loop can do this better is just being closed minded. You're comparing a $1000 elaborate closed loop system to a $50 maxijet, try comparing apples to apples. They also produce much less vibration than most external pumps and will always come out on top in efficiency. Heat transfer through a Tunze is minimal wouldn't add sufficient heat to a system to require cooling. Vortecs have there motors external so they would add even less heat to the system.

The only real advantage to a closed loop is that intakes and outputs can sometimes be hidden better, however both Tunze and Vortec offer solutions for this as well. Closed loops can also be a better alternative for extremely large aquariums where you simply can't get power heads large enough but most hobbyists don't have tanks that large.

I've used Tunze power heads in my tanks and others I maintain for well over 5 years and the very few problems I have had where quickly fixed free of charge by the manufacturer despite the fact that the warranty was expired and I had no proof of purchase. I can't say the same for many external pumps I have used which have certainly proved to be less reliable than the power heads I've used. External pumps that use external motors are far from reliable, seals often fail which quickly leads to bearing failure.

Closed loops are usually done as a cheaper alternative to expensive power heads, not the opposite. And the they slowly being phased out as more and more advancements are being made with DC power heads. An external DC pump could make a come back for CLs but so far something reliable and cost effective hasn't been made available to us.

Head Loss Info, FYI

Excel Sheet (http://www.google.ca/url?sa=t&source=web&ct=res&cd=1&ved=0CAcQFjAA&url=http%3A%2F%2Fwww.advancedaquarist.com%2Fissues %2Fjan2003%2Fwaterpipe-v1.xls&rct=j&q=pipe+losses+site%3Awww.advancedaquarist.com%2F+&ei=-p3YSqi4DYil8Abblr23BQ&usg=AFQjCNF-JQbdKZKl3647I-o-6Uv-J0ZODQ)

http://www.advancedaquarist.com/issues/jan2003/featurejp.htm

sphelps
10-16-2009, 05:26 PM
We are not really talking apples to apples here, both vortech and tunze claim flow numbers that becomes converted to gallons per hour of flow.
I would not argue their claims in the slightest, but just for a second could you answer me one simple question, if a vortech or tunze produce 3000- gph of flow , and you throttle back a dart to produce 3000 gph would the result be the same?
Tunzes and Vortecs push flow outwards in an expanding direction, this results in a larger area and therefore a lower velocity. Velocity is not that same as flow rate.

mr.wilson
10-16-2009, 05:36 PM
Thanks for posting that article, Dana Riddle is an excellent source. It's good to see hard numbers and it's a shame that manufacturers won't spend the resources to achieve this themselves.

As I stated before, Vortechs work around most of the potential problems that arise from powerhead applications. I still argue that they have the following drawbacks...

1) Only suitable to be located at opposing ends of the tank. They cannot be located on the front, or easily on the back, or on the bottom, or within the reef structure, as closed loops can.
2) They are not directional, meaning they are limited to pointing forward (not up or down or at any other angle).
3) They cannot be easily disguised inside or outside of the tank.
4) They require a network of wires running around the outside of the tank.
5) They are slightly louder than a closed loop pump. CL pumps can be remote, while Vortechs must be on the side of the tank.
6) They give off more heat transfer directly to the tank wall (some acrylic tanks have had stress crack issues. According to Riddle, the external temperature is 138F.
7) They cause vibration within the tank which can disturb livestock.
8) Circular or laminar flow is not possible with Vortechs. Water travels in one direction from end to end hitting the opposing wall or opposing flow. I read the velocity numbers, but I don't have pressure pump values to compare them with.
9) I don't know how often Vortechs need to be serviced, but CL pumps have at least 10 years before the volute needs to be looked at. Calcification only occurs on metallic pumps, so magnet coupled pressure pumps don't need to be soaked in acid. Vortechs have not been on the market long enough to establish longevity.
10) There's always a #10. Vortechs are hard to use with tanks that have cabinetry that covers end walls or aquariums fit into walls where access is limited.

The extra 100 watts used by a closed loop pump (if that is truly the case) would not be 100% heat generation, and even if it was, it wouldn't impact the cooling system of a house. These days most people open windows before they turn on the A/C. I'm not about to argue that it contributes to heating your home in winter either :)

In my opinion, the flow from a closed loop pump has more flexibility to be used for better flow dynamics than a Vortech system. By no means does this make a closed loop system a license to use poor flow placement, nor does it exclude Vortechs from fulfilling some of the flow requirements of a tank.

If optimum flow dynamics are in place, which is more readily achievable with a closed loop system, a 15x turnover ratio can be just as effective as a 40x turnover ratio. It is arguable, that 3600 GPH with a closed loop is worth 4800 GPH from a well configured Vortech system.

If you aren't particular about aesthetics or flow dynamics, then Vortechs will work well for you. If you feel you can recoup the initial cost of a series of Vortechs with energy savings, then it has further added value.

golf nut
10-16-2009, 05:40 PM
Tunzes and Vortecs push flow outwards in an expanding direction, this results in a larger area and therefore a lower velocity. Velocity is not that same as flow rate.

That wasn't what I asked, so I will rephrase, if I throttle back a Dart to 3000 gph and make the outputs disperse similar to a tunze or vortech would they be similar?

sphelps
10-16-2009, 05:50 PM
That wasn't what I asked, so I will rephrase, if I throttle back a Dart to 3000 gph and make the outputs disperse similar to a tunze or vortech would they be similar?
Yes and no, same flow rate different velocity. The lower velocity and greater spread creates an advantage as simulates natural water movement better.

http://www.jlaquatics.com/images/tunze/6080-main.jpg

littlesilvermax
10-16-2009, 05:53 PM
We are not really talking apples to apples here, both vortech and tunze claim flow numbers that becomes converted to gallons per hour of flow.
I would not argue their claims in the slightest, but just for a second could you answer me one simple question, if a vortech or tunze produce 3000- gph of flow , and you throttle back a dart to produce 3000 gph would the result be the same?


I know what you are saying, and totally agree.

3000 gph from a dart will INDUCE a lot more flow then that in the tank. it is hard to compare that with a tunze or similar powerhead.

golf nut
10-16-2009, 05:53 PM
So we agree that if I could make the outlets of a Dart replicate the Tunze/vortech with the dart throttled to be the same as the flow then we would have identical flow?

mr.wilson
10-16-2009, 06:18 PM
Comments like this make me question your design experience, while I wouldn't expect most hobbyists to understand pipe dynamics I would expect an experienced designer to understand some basics regarding flow mechanics in piping systems. Static head is only one part of head loss and even with correct pipe sizes and flexible pipe friction losses are large and plumbing the pump into the basement would add huge losses from friction. You can never completely avoid elbows, tees, unions, and ball valves. These all add significant losses. In addition adding systems to rotate flow will also add significant losses. But your major losses will always come from pipe length and over time your roughness factor increases adding more friction to the system.

I stated there was no head loss, not that there was no friction loss. I was responding to your comment about head loss with closed loop pumps being significant. If you use the RC flow calculator you will see that an elbow, two ball valves and 15' of pipe will drop a Blueline 70 from 1710 GPH to 1620 GPH. This is an example of a closed loop pump located in a basement below the tank, you would have less friction if it were located directly below the tank and of course you could add friction with other plumbing. I simply don't see this as a significant issue, and you never mentioned it in your comparison for likely the same reason.

A good power head like a controllable tunze or vortec is a far superior option. They can be controlled by microprocessors and tuned to a frequency that matches your tank dimensions resulting in maximum water movement with minimal power consumption. The flow control is electronic which allows for unlimited possibilities for both flow control and dynamics. To say a closed loop can do this better is just being closed minded. You're comparing a $1000 elaborate closed loop system to a $50 maxijet, try comparing apples to apples. They also produce much less vibration than most external pumps and will always come out on top in efficiency. Heat transfer through a Tunze is minimal wouldn't add sufficient heat to a system to require cooling. Vortecs have there motors external so they would add even less heat to the system.

What are you trying to accomplish with variable speed on the Vortechs or Streams? An intermittent reduction in output only reduces the volume of water you are moving (and electrical consumption). An Oceansmotions 4 Way maintains the same flow rate within the tank while offering a passive surge and allows detritus to momentarily settle for coral feeding, then pick up again before it reaches the substrate. If you time the ports properly, detritus can be passed from one end of the tank to the other using 50% less flow than four static effluents. A powerhead system is limited to side to side flow, and while one side is off, your flow is now at 50% capacity. A closed loop pump with a 4 way is always delivering the right amount of water to right location at all times. You would need twice as many powerheads to make up for the time they are not running for side to side motion.

The only real advantage to a closed loop is that intakes and outputs can sometimes be hidden better, however both Tunze and Vortec offer solutions for this as well. Closed loops can also be a better alternative for extremely large aquariums where you simply can't get power heads large enough but most hobbyists don't have tanks that large.

What are the solutions that they offer. The Dana Riddle article confirmed some of the flow claims so they got some points with me for that, and I would be happy to hear about more hidden benefits.

I've used Tunze power heads in my tanks and others I maintain for well over 5 years and the very few problems I have had where quickly fixed free of charge by the manufacturer despite the fact that the warranty was expired and I had no proof of purchase. I can't say the same for many external pumps I have used which have certainly proved to be less reliable than the power heads I've used. External pumps that use external motors are far from reliable, seals often fail which quickly leads to bearing failure.

Shaft driven pumps like Sequence are not suitable for marine aquariums so I'm not surprised you had problems, but that is like me directly comparing a maxijet to a Vortech, which I have not. The main problem hobbyists experience with external pumps is sumps running dry (which would also happen with a submersible pump), and saltwater dripping on the motor (which is negligence). To a lesser extent sand in the impeller or dust in the fan also occur, but once again these same people would be negligent with powerheads. I have experienced a 1% return or repair issue with external pumps, and although I don't use powerheads, I always see a mountain of them at local aquarium stores return bins and replacement parts are well stocked, while replacement parts for external pumps is a non-issue.

Closed loops are usually done as a cheaper alternative to expensive power heads, not the opposite. And the they slowly being phased out as more and more advancements are being made with DC power heads. An external DC pump could make a come back for CLs but so far something reliable and cost effective hasn't been made available to us.

Sequence makes a DC Dart. The only application I could see is a series of deep charge marine batteries for a backup system but personally I prefer air lifts.

Head Loss Info, FYI

Excel Sheet (http://www.google.ca/url?sa=t&source=web&ct=res&cd=1&ved=0CAcQFjAA&url=http%3A%2F%2Fwww.advancedaquarist.com%2Fissues %2Fjan2003%2Fwaterpipe-v1.xls&rct=j&q=pipe+losses+site%3Awww.advancedaquarist.com%2F+&ei=-p3YSqi4DYil8Abblr23BQ&usg=AFQjCNF-JQbdKZKl3647I-o-6Uv-J0ZODQ)

http://www.advancedaquarist.com/issues/jan2003/featurejp.htm[/QUOTE]

mr.wilson
10-16-2009, 06:20 PM
Tunzes and Vortecs push flow outwards in an expanding direction, this results in a larger area and therefore a lower velocity. Velocity is not that same as flow rate.

It also results in detritus being pushed down into the substrate rather than up to the surface for suspension, surface skimming and gas exchange.

If you like the outward flow of a Vortech, it can be easily replicated on a closed loop with a penductor, or a series of them if you split your closed loop into several ports.

sphelps
10-16-2009, 07:02 PM
Vortecs have the advantage of the external motor which of course presents limitations however hobbyists have the choice to use them when appropriate and could also use Tunzes which solve many of these limitations.

1) Only suitable to be located at opposing ends of the tank. They cannot be located on the front, or easily on the back, or on the bottom, or within the reef structure, as closed loops can.
They can be located virtually anywhere, including within the reef structure. Maybe not as desirable in some locations but they also have the advantage of relocation if aquascaping or flow demands change, not as easy with closed loops. These pumps also have the advantage to pulse at critical frequencies to produce a natural wave type movement. Corals do not benefit from direct flow so I don't even see the advantage of pointing flow directly at the reef structure.

2) They are not directional, meaning they are limited to pointing forward (not up or down or at any other angle).
Tunzes are certainly directional, the new models have movement in almost all directions.
"they offer a lot of flexibility with respect to positioning and orientation of the water stream, which can be adjusted in such a way that an effective flow is produced over a long distance in the aquarium at lower power consumption."


3) They cannot be easily disguised inside or outside of the tank.
http://www.tunze.com/typo3temp/pics/d9e89990f2.jpg

4) They require a network of wires running around the outside of the tank.
Cables can be tied back to one location like the back of the tank, or if all sides are viewable through the overflow.

5) They are slightly louder than a closed loop pump. CL pumps can be remote, while Vortechs must be on the side of the tank.
The further remote the more friction loss and most don't like to run large PVC pipe through their house. Vortecs are virtually silent if balanced correctly, and you can't even hear a Tunze running. CL pumps like a Dart are very noisy in comparison.

6) They give off more heat transfer directly to the tank wall (some acrylic tanks have had stress crack issues. According to Riddle, the external temperature is 138F.
Splitting hairs, heat will transfer from the motor to the water moving through an external pump in a similar fashion. The housings on the dart pumps I owned were warm to the touch and I've seen similar pumps fail when flow valves were shut and forgotten about. The pump is air cooled but still relies on the flowing water to remove part of the heat produced.


7) They cause vibration within the tank which can disturb livestock.
Interesting theory but I asked my fish this morning, they don't mind it. Pumps can also be turned down over night with controllers and create a more calming environment.

8) Circular or laminar flow is not possible with Vortechs. Water travels in one direction from end to end hitting the opposing wall or opposing flow. I read the velocity numbers, but I don't have pressure pump values to compare them with.
Turbulent flow could be a good thing as it would create a more random flow pattern adding to the snow globe effect. However you may have it backwards, a Tunze or Vortec spreads flow out over a larger area creating lower velocity which would promote a more laminar environment, closed loops often use jets which create high velocity patterns which disturb the water around it creating a turbulent boundary layer.

9) I don't know how often Vortechs need to be serviced, but CL pumps have at least 10 years before the volute needs to be looked at. Calcification only occurs on metallic pumps, so magnet coupled pressure pumps don't need to be soaked in acid. Vortechs have not been on the market long enough to establish longevity.
Completely false, external pumps, shaft driven, or magnetically driven, require frequent maintenance. Magnetically driven pumps require impeller and shaft cleaning as often as any power head. Shaft driven pumps also require frequent cleaning to prevent seal failure and build up which creates both resistance and noise. When I had issues with my reeflo dart the manufacturer stated the the impeller housing must be flushed and cleaned every three months to prevent seal failure. The seal also should be constantly checked for salt creep for the same reason.

10) There's always a #10. Vortechs are hard to use with tanks that have cabinetry that covers end walls or aquariums fit into walls where access is limited.
So a closed loop is easy to access with limited cabinetry access? I can't see how in most aquariums a closed loop offers easier access than power heads like tunze and vortec.


In my mind quality power heads like Tunze and Vortec offer the following advantages over CLs.

1) Easier setup and maintenance
2) Better resale and easier to incorporate in new tanks. Plumbing for a closed loop is expensive, I did a 4W OM on a clients tank and it cost around $400, very rarely can plumbing parts transfer to a new tank.
3) Can be relocated at anytime with minimal effort
4) Can be upgraded or down graded without major modifications to the tank
5) Use less power, greater efficiency a dart runs 22.5 GPH/W while a Tunze Stream 6000 runs 123.2 GPH/W
6) Create less noise, sorry but a tunze is quieter than a dart
7) Much better flow control and have better capability to produce more natural wave flow. The vast selection of electronic controllers is far superior to the OM and SCWD devices which are only ones I'm aware of.
8) Simplicity, closed loop systems require more experience in plumbing. You also can't really contain both a closed loop system and a sump system in one stand, it would have to oversized or very tight making maintenance a nightmare.
9) No tank modifications needed, Closed loops require a swiss cheese tank to hide the plumbing
10) Better reliability all the way round. The external plumbing required for a closed loop can be a dangerous game, bulkheads can leak down the road and replacement would be a tremendous headache requiring the complete dismantle of an established aquarium. People worry enough about the actual tank seams leaking, why add more potential for leaks?

I could go on but 10 seems to be the magic number.

sphelps
10-16-2009, 07:30 PM
I stated there was no head loss, not that there was no friction loss. I was responding to your comment about head loss with closed loop pumps being significant. If you use the RC flow calculator you will see that an elbow, two ball valves and 15' of pipe will drop a Blueline 70 from 1710 GPH to 1620 GPH. This is an example of a closed loop pump located in a basement below the tank, you would have less friction if it were located directly below the tank and of course you could add friction with other plumbing. I simply don't see this as a significant issue, and you never mentioned it in your comparison for likely the same reason.

Yes very good but that's over 8 feet of head pressure, it's significant but its a pressure rated pump so flow losses are minimal with added pressure. How much power is that using? Around 300W, ouch! not something I would want to run. And exactly who can plumb a closed loop with such little fittings? Take the same case but more realistic and add 3 more elbows, 4 more ball valves, 6 unions, over 4 exists and you'll see that jump up to 13 feet. Then compare that to a more common pump like a dart and you'll get just over 10 feet which drops the flow from 3600 to 1200. You did state that friction exists but it was small, this simply isn't true and there would be a huge difference in plumbing to the basement, add 20 more feet of pipe and pressure jumps to 16.5 feet on the blueline. And none of that even considers what that OM does for head loss, I wouldn't even want to know.


What are you trying to accomplish with variable speed on the Vortechs or Streams? An intermittent reduction in output only reduces the volume of water you are moving (and electrical consumption). An Oceansmotions 4 Way maintains the same flow rate within the tank while offering a passive surge and allows detritus to momentarily settle for coral feeding, then pick up again before it reaches the substrate. If you time the ports properly, detritus can be passed from one end of the tank to the other using 50% less flow than four static effluents. A powerhead system is limited to side to side flow, and while one side is off, your flow is now at 50% capacity. A closed loop pump with a 4 way is always delivering the right amount of water to right location at all times. You would need twice as many powerheads to make up for the time they are not running for side to side motion.
You're obviously not too familiar with what my profilux controller can do with my Tunzes, way beyond side to side movement and simple pulses. From sine waves to right angle shorts and random % additions plus storm simulations natural wave movements and night modes I'm sorry but it does way more good than a OM. You could do the exact same as an OM with such power heads at that would be the simplest program, but nobody would because the other options are better.



What are the solutions that they offer. The Dana Riddle article confirmed some of the flow claims so they got some points with me for that, and I would be happy to hear about more hidden benefits.
Check out that nice picture I already posted, rock covers can hide such power heads just like a closed loop.


Shaft driven pumps like Sequence are not suitable for marine aquariums so I'm not surprised you had problems, but that is like me directly comparing a maxijet to a Vortech, which I have not. The main problem hobbyists experience with external pumps is sumps running dry (which would also happen with a submersible pump), and saltwater dripping on the motor (which is negligence). To a lesser extent sand in the impeller or dust in the fan also occur, but once again these same people would be negligent with powerheads. I have experienced a 1% return or repair issue with external pumps, and although I don't use powerheads, I always see a mountain of them at local aquarium stores return bins and replacement parts are well stocked, while replacement parts for external pumps is a non-issue.
All the external pumps who have recommended are shaft drive, aren't they? I used darts as an example because you mentioned them in a previous post.

Sequence makes a DC Dart. The only application I could see is a series of deep charge marine batteries for a backup system but personally I prefer air lifts.
Good stuff, so no comebacks for CLs :mrgreen:

mr.wilson
10-16-2009, 08:15 PM
I was responding to the comments that Canadian had made about Vortechs. Vortechs are easily the best powerhead on the market, if you can still call them a powerhead, more of a magnet spinner. They address most of the problems that submersible pumps cause. If I was talking about Tunze pumps I would have address different issues.

The only reference I have of sound was from the Dana Riddle article where he claimed they have a whine which increase in frequency as they power up and down. I've seen them is use on tanks, but only in fish rooms or noisy hobbyist tanks.

Tunze powerheads can be located anywhere, but they need to be removed for periodic servicing and they have moving parts in the reef. I don't agree that magnet coupled chemical pumps with sealed bearings such as Iwaki require preventative maintenance or volute cleaning. It appears that you experience is limited to non-chemical pool pumps like the Sequence line, so I understand why you don't like closed loop systems. This line of thought is equally as unfair as me comparing a Vertech pump to a maxijet, which I have not done.

I'll admit some of the issues I have listed are not significant drawbacks, like extra power cords, but it was a simple comparison of pros and cons just as I would accept that Dart pump is too loud for a home aquarium and it isn't suitable for marine applications.

I agree heat transfer comparisons are splitting hairs. I was just using Dana Riddles comments about heat in comparison to Canadian's claims of added air conditioning costs to counter the heat thrown from a closed loop pump. They both have external temperatures of 130F, it's just closed loop pumps use heat sinks and fans to mask the heat. You could easily put a fan on a Vortech if it was ever an issue, and I doubt it would.

I don't have the time or desire to look up articles about vibration or moving parts in reef aquariums. They may or may not affect the physiology of fish and invertebrates, but it remains as something to consider when weighing options. Your claim that you can tell it doesn't effect your fish is silly.

Turbulent flow doers not create random flow patterns. They may be more intricate, but they are not random unless you have programmed sporadic sequences into your powerhead controller.

You have to make up your mind about the flow you are endorsing. One minute you are talking about prop powerheads offering lower velocity and fanned out, diffused flow as being beneficial, and in the next paragraph you are saying a closed loop pump has too much velocity so it moves too much water as it passes through the tank. If it moves more water than the amount measured leaving the effluent port, then let's add that to the total flow rate as we should.

My point about pump access with a closed loop was you unplug the pump and shut off two union valves and you can remove it to service, upsize or downsize. With Powerheads you may have to move corals if you have them within the rock work. Vortechs are easy to access because they don't work in these locations and don't utilize suction cups or plastic clips.


In my mind quality power heads like Tunze and Vortec offer the following advantages over CLs.

1) Easier setup and maintenance
Easier set-up, harder maintenance. Closed loop owners forget they are even there, while powerheads are part of routine servicing.
2) Better resale and easier to incorporate in new tanks. Plumbing for a closed loop is expensive, I did a 4W OM on a clients tank and it cost around $400, very rarely can plumbing parts transfer to a new tank.
I don't know which would have a better residual value, but it's a strange benefit to consider. For that reason, I'll give you the point.
3) Can be relocated at anytime with minimal effort
Absolutely, but you will never get it where it works best.
4) Can be upgraded or down graded without major modifications to the tank
Just as a closed loop pump can. A 1" in and out port will fit hundreds of pump possibilities. Once again, planning for re-engineering is a poor selling point.
5) Use less power, greater efficiency a dart runs 22.5 GPH/W while a Tunze Stream 6000 runs 123.2 GPH/W
This is only true if you are measuring strictly the water exiting the effluent port and not the overall effect. The trade off with high volume low energy consumption pumps is velocity. There are arguments for both high and low velocity systems. Closed loop systems can simultaneously offer both with a wave making device, while powerheads are limited to low velocity, lower velocity, and no velocity. Energy savings are nominal. While they may be 50% in the best of scenarios, the hard number is $5-10 a month. In a society where we drive cars that get 20MPG while 60MPG cars are readily available, it's a hard sale. How often do you fill up your BMW gas tank? Whatever you are spending, it's three times higher than what it could be.

6) Create less noise, sorry but a tunze is quieter than a dart

Once again if you are going to compare to a Dart then I will use an oil cooled cast iron sump pump as a basis for powerhead comparisons :) An Iwaki or Panworld 70 located in a remote location away from the cabinet will not be audible at all. Alternatively a Red Dragon, Deltec or Poseidon pump is also inaudible.

7) Much better flow control and have better capability to produce more natural wave flow. The vast selection of electronic controllers is far superior to the OM and SCWD devices which are only ones I'm aware of.

Then you have proven once again that your knowledge is limited.

8) Simplicity, closed loop systems require more experience in plumbing.

Absolutely, just as proper Tunze Stream placement requires more experience than putting them in the corner where they look good.

9) No tank modifications needed, Closed loops require a swiss cheese tank to hide the plumbing

There is no reason why a closed loop system with an external pump requires and holes in the tank. If you can live with powerheads in the tank and hanging off of the side, then a few pipes running over the trim at the back should not be a problem.

10) Better reliability all the way round. The external plumbing required for a closed loop can be a dangerous game, bulkheads can leak down the road and replacement would be a tremendous headache requiring the complete dismantle of an established aquarium. People worry enough about the actual tank seams leaking, why add more potential for leaks?

First of all, I was right, there is always a #10. You are absolutely correct, a tank full of extra valves, fittings and bulkheads is a liability, especially if it is not done properly. It's a very small liability, but it still exists. A closed loop system with external plumbing running over the trim saves the cost of extra holes, bulkheads and valves. I see a need for only two drain holes with anything else being a luxury. Doesn't your tank have four holes in the bottom? This adds the extra cost of tempering and or a thicker bottom panel. The bottom is the easiest panel to get a leak with as there is more hydrostatic pressure on it and long pipes can bend and cause water to leak past the bulkhead flange.

I could go on but 10 seems to be the magic number.

At least we agree on something :)

mr.wilson
10-16-2009, 08:34 PM
Yes very good but that's over 8 feet of head pressure, it's significant but its a pressure rated pump so flow losses are minimal with added pressure. How much power is that using? Around 300W, ouch! not something I would want to run. And exactly who can plumb a closed loop with such little fittings? Take the same case but more realistic and add 3 more elbows, 4 more ball valves, 6 unions, over 4 exists and you'll see that jump up to 13 feet. Then compare that to a more common pump like a dart and you'll get just over 10 feet which drops the flow from 3600 to 1200. You did state that friction exists but it was small, this simply isn't true and there would be a huge difference in plumbing to the basement, add 20 more feet of pipe and pressure jumps to 16.5 feet on the blueline. And none of that even considers what that OM does for head loss, I wouldn't even want to know.

This is why your use of a Dart was foolish, but you know that now. The total flow loss with a pressure pump is far less than a Red Dragon return pump with only 5' of head.

You're obviously not too familiar with what my profilux controller can do with my Tunzes, way beyond side to side movement and simple pulses. From sine waves to right angle shorts and random % additions plus storm simulations natural wave movements and night modes I'm sorry but it does way more good than a OM. You could do the exact same as an OM with such power heads at that would be the simplest program, but nobody would because the other options are better.

You need to stop comparing my Vortech comments to your Tunze pumps. I know you have more options than a Vortech with regard to positioning but you are still limited, and as such you cannot do what a closed loop can. If I were to choose an alternative method, I would go with the Vortech, not the Tunze. Yes I am familiar with the Profilux controller coupled with the Tunze pumps. I service two tanks that have that combination.

Check out that nice picture I already posted, rock covers can hide such power heads just like a closed loop.

Yes, but they are transient. You still have an electrical cord in salt water and moving parts in your reef. Once you put that faux rock on the powerhead you are losing whatever intake flow dynamics you were hoping for with your Tunze.

All the external pumps who have recommended are shaft drive, aren't they? I used darts as an example because you mentioned them in a previous post.

I think you have me confused with the other guy. If I mentioned Sequence pumps it was only because they are commonly used in the hobby, just as I would refer to a maxijet or Magdrive pump even though I don't use them.

Vortech has taken powerheads to a new level. It isn't a new idea by any means. Aquarium pump manufacturers should be ashamed that it took so long to adapt a simple magnet spinner to the tank. They have been around for over 50 years in the scientific community and they were used in Dynaflow filters in the 70's and Marineland filters in the 80's.

It's too bad there have been no major advances in pressure rated chemical pumps in the past 30 years.

sphelps
10-16-2009, 08:54 PM
Well we could go on forever, I still obviously don't agree with all your points and you obviously don't agree on mine. We can always find something pick at and spin against one another so before this gets out of hand again I'm agreeing that closed loops are a good option if done correctly and the space is available. However I personally prefer the use of certain power heads for the reasons stated and not because of my lack of experience or knowledge of closed loops.

I would have been better to have this discussion with a broader audience, I find threads like this quickly die on this site and you end up in this exact position :sad:

Not that this would particularly prove anything but I think it would be interesting to setup a poll or two to see what other hobbyists find and believe works before for water flow.

mr.wilson
10-16-2009, 09:07 PM
I find that these threads get a good audience. There are over 1200 views thus far, which isn't bad for a new thread with no answers, pictures or swearing.

I fully agree that powerheads are a sound choice for some people. It was never a matter of one being wrong and one being right, but one of which one is right for whom.

Unfortunately we don't have much science to help the situation. We have a Dana Riddle article that gives ratings for Vortech pumps but without flow ratings for external closed loop pumps we are still comparing apples to oranges.

I'm sure a poll would determine that powerheads are more popular, but as you mentioned it doesn't prove anything. I guess I have to go back to work then :(

sphelps
10-16-2009, 09:28 PM
Yes lots of viewers but few writers. What I meant to say was these threads often die because it comes down to a couple people saying the same thing over and over again and it would be better if more people would pipe in with their opinions and experience. Group thinking and discussions are always better in my mind and the more people in the group the better. It's like classic statistics, if you have a jar of gum balls and have to guess how many is in the jar stats proves that the average number of a large group of people will be always be closer than one individual guess. Of course luck isn't considered in stats :wink:

mr.wilson
10-16-2009, 09:33 PM
Okay. I guess 710 gumballs.

sphelps
10-16-2009, 09:40 PM
Okay. I guess 710 gumballs.
Hahahaha, get back to work

speaking of work I should really get back to it as well, this is what my desk currently looks like :redface: Cleaned it last week :sad:

http://i11.photobucket.com/albums/a174/sphelps/misc/desk1.jpghttp://i11.photobucket.com/albums/a174/sphelps/misc/desk2.jpghttp://i11.photobucket.com/albums/a174/sphelps/misc/desk3.jpg

Parker
10-16-2009, 10:13 PM
Can I be honest?

I believe the thread got a lot of views simply because there may have been a hint of tension.

As for thoughtful discussion on what might be the better option. The decision to use one method over the other is primarily based on personal preference. If you asked most people, what they have in place in their own tanks is the stance they would take. They chose their method of water movement for reasons known only to them. I would be willing to bet most people didn't choose via published stats.. IE: Laminar Flow and watts/gph but rather what they could afford at the time or how they wanted the tank to look.

These are my thoughts only.. I'm probably the dumbest person in this thread!
:redface:

golf nut
10-16-2009, 11:19 PM
Yes and no, same flow rate different velocity. The lower velocity and greater spread creates an advantage as simulates natural water movement better.

http://www.jlaquatics.com/images/tunze/6080-main.jpg


So we agree that if I could make the outlets of a Dart replicate the Tunze/vortech with the dart throttled to be the same as the flow from the vortech/tunze then we would have identical flow?

sphelps
10-16-2009, 11:52 PM
So we agree that if I could make the outlets of a Dart replicate the Tunze/vortech with the dart throttled to be the same as the flow from the vortech/tunze then we would have identical flow?
well not quite. A propeller pushes flow outward so it would take more than simply matching nozzle size, you would need some kind of special adapter on the dart outlet to produce the same results, but if that was the case yes I believe the results would be identical. Other than one uses 15W and the other uses 150W.

Seems strange you want to confirm this so badly, do you have a point you plan on springing on me once I agreed? :lol:

golf nut
10-17-2009, 12:12 AM
Seems strange you want to confirm this so badly, do you have a point you plan on springing on me once I agreed? :lol:

Of course.:)