how many times a hour should the water go through the sump?

[mr.wilson]

Originally Posted by StirCrazy

Ok this whole thing is bing made a lot more complacated that it has to be. let me try clarafy and put an end to the back and forth which is getting no where and just confusing people reading this.

Ok so I will put forth 2 senarios for you to read and tell me which one works better all equipment is the same so tank is 80 gal sump is 30 gal, skimmer is fed by a 500gph pump

so senario 1, lets match the skimmer so the return flow is 500 gal per hour

Senario 2, lets use a bigger return pump so the flow is 1500 gph.

and heck let throw one more in
senario 3 lets match the tank, flow rate is 30 gal per hour.

so in senarios 1+2 the skimmer is given all the water it can handle but yet in senario 3 you are starving the skimmer.

so lets pick a number and say that this skimmer is 20% efficient (picked 20 as it is easier to work with) which means in 1 hour this skimmer will reduce the "crap" in 500gal of water by 20%

so our total water volume in these systems is the same at 100gal

system 1 the skimmer has all the water it can handle so it reduces the waist to it theoretical maximum reduction. as per the article Mr Wilson poster that is about a 80% removal.

in system number 2, the exact same amount of water is processed, so you get the same results as system 1.

but in system 3 where we matched the tank size for a 1X turnover, the skimmer only sees 80gal in that hour, but since it skimms the hell out of that 80 gal it is reduced to the max pull down so 80% clean 20% dirty then mixed with the 100% dirty water in the display so 80 gal at 20% mixed with 20 gal at 100% is going to give you about a 35% dirty mixture as aposed to the 20% from the first 2. so you can see if we matched the sump flow for a 1X turn over it would be even worse as we would have 20 gal of 80% clean water mixing with 80 gal of 100% dirty, which would end up with a number of 84% dirty.

So what do we get from this, not enough flow is very bad, to much flow works good but isn't efficient in power used for moving the water.

I really don't see how that simplified matters.

In example one we have high efficiency.

In example two we have a waste of resources (extra drain noise, additional plumbing, more expensive pump, saltcreep, microbubbles, added heat and noise from larger pump etc. etc.). There is a lot more to it than "to much flow works good but isn't efficient in power used for moving the water." Protein skimmers are designed to maintain bubble stability long enough to deliver the "bad stuff" to the collection cup. Once you lower salinity, add ozone, or decrease the concentration of "bad stuff" you compromise the stability with a net result of premature bubble merging and popping (wet foam). This is why protein skimmer must be sized correctly for the tank and subsequent bioload it is intended for. Installing an oversized skimmer on a tank will often result in poor foam development.

In example three we are giving the skimmer a deficit of "dirty" water, and falling short of the manufacturer's feed requirements. Whatever the shortfall is, will be your rate of inefficiency. Unless you are prepared to challenge the skimmer manufacturer's recommended feed amount for a slower feed, you have a net loss of efficiency. Extra passes through the skimmer with the same effluent water that has just been skimmed is not the same as increasing contact time and does not "skim the hell out of the water".

Your math is incorrect in scenario three as well. The skimmer is fed new "dirty" water at a rate of 80 gallons per hour. Providing you agree that a FIFO system is the most efficient, some of that water will be processed once, while other molecules will be processed many times. There is actually a formula for this in Escobal's book that you disagree with.

How can you assume that you are getting "max pulldown" by reskimming the same water over and over at that unknown rate. Based on a feed of 80 GPH and skimmer pump output of 500 GPH, the water will pass through the protein skimmer 6.25 times per hour, providing your design incorporates a way of telling how many times each molecule has travelled through the skimmer before returning to the display A FIFO design can assure that all 80 GPH passes through once, but after that it's entirely random.

Originally Posted by StirCrazy

heaters will work just as good in high flow as in low flow but they transfer more heat to a perticular sample of water in a lower flow, but in a closed system where we have constant cirulation the end result will be the same. and to low a flow can cause heat gradiants which you don't want. as for UV this is a hard one as you have to match the flow written on the UV unit.. mine wanter 400 to 550 gph so I gave it a 550gph pump and knew there would be between 50 and 100gph of losses, chiller same thing match the flow rating.

Heaters rarely come on in reef tanks, but I still install them nonetheless. Debating their maximum efficiency at the cost of the other equipment you will actually use on a daily basis is moot. There is a difference between manufacturer's directions and scientific formulas for zap rates. If you want efficiency, then use Escobal's formula. Here is a simplified version you can follow. http://www.aquariumadvice.com/articl...ers/Page1.html
A typical 25 watt UV sterilizer works most efficiently at 80 GPH throughput.

Originally Posted by StirCrazy

so the way I had my tank set up I created massive amounts of flow in the display to keep everythign suspended. my surface was very turbulant so I never developed bio film that needed to be skimmed off the surface. but I still used a smooth overflow to reduce noise and I had the water flowing over it at a depth of about 1/4" so I would have enough water flow to carry suspended junk to the sump.

Proteins are polar, with one end being hydrophilic (attracted to water/repelled by air) and the other hydrophobic (repelled by water/attracted to air). Protein constantly switch polarity back and forth, so when we collect surface water it is always rich in hydrophobic proteins, or surfactants (surface active agents).

Originally Posted by StirCrazy

from the sump I had one pump tt remove water for my skimmer, this sucked from my settling pond and returned at the return pump chamber, my heaters were located in the settleing pond where the flow was a little lower. I had two pumps pull water out of the return pump chamber and send it to the chiller and the UV then return at the very bigining again to help keep the flow in the bigining section very fast and turbulant so any suspended matter wouldn't fall out befor the settling pond.

the result of this system was very very little cleaning of crap from the bottom of the desplay, but lots from the settling pond which is what I wanted. I would shut down the return pump, skimmer pump and UV pump, suck all the water from the settling area (about 20) then put my new salt water in there and water change and clean up was done. I don't like refuge, algae or anything else in the sump, as they do need a low flow, so I had my refuge remote and I pumped water to it and it trickeled back into the display directly.

Steve

Chaetomorpha and Gracilaria do very well under high flow rates, but it isn't a requirement.

I don't understand why you wanted high flow in your sump? I like the idea of a settling chamber, but it should be slow moving and at the base of the first zone (skimmer/settling/mechanical filtration). Also why not use one pump for the chiller and UV unit? By returning these effluents (UV & chiller) to the beginning of your sump, you are irradiating the water two or more times, and getting a heat gain by not sending the chilled water directly to the tank. It looks like your system is a "water juggler" with a lot of resources expended to complete a simple task. By you description, your sump served two purposes 1) House the protein skimmer. 2) House a settling chamber. The rest of the equipment you mentioned is either a header tank or inline. Why not put the skimmer in the refugium header tank?

[StirCrazy]

Originally Posted by mr.wilson

I
Your math is incorrect in scenario three as well. The skimmer is fed new "dirty" water at a rate of 80 gallons per hour. Providing you agree that a FIFO system is the most efficient, some of that water will be processed once, while other molecules will be processed many times. There is actually a formula for this in Escobal's book that you disagree with.

which math, and it was all just off the top of my head.. it is close enough for this discussion.

Originally Posted by mr.wilson

How can you assume that you are getting "max pulldown" by reskimming the same water over and over at that unknown rate. Based on a feed of 80 GPH and skimmer pump output of 500 GPH, the water will pass through the protein skimmer 6.25 times per hour, providing your design incorporates a way of telling how many times each molecule has travelled through the skimmer before returning to the display A FIFO design can assure that all 80 GPH passes through once, but after that it's entirely random.

We can assume that if this is happening we have a hell of a lot better chance of getting a better pulldown than if we put 500 gph or 1500 gph through the sump. the point is the skimmer is going to skim the same amount of water weather it is the same water (or portion there of) over and over or some of the new water going buy. and what does FIFO stand for?? I hate abreabiations as everyone makes them up and doesnt state them on the first use like they should.

Originally Posted by mr.wilson

I don't understand why you wanted high flow in your sump? I like the idea of a settling chamber, but it should be slow moving and at the base of the first zone (skimmer/settling/mechanical filtration). Also why not use one pump for the chiller and UV unit? By returning these effluents (UV & chiller) to the beginning of your sump, you are irradiating the water two or more times, and getting a heat gain by not sending the chilled water directly to the tank. It looks like your system is a "water juggler" with a lot of resources expended to complete a simple task. By you description, your sump served two purposes 1) House the protein skimmer. 2) House a settling chamber. The rest of the equipment you mentioned is either a header tank or inline. Why not put the skimmer in the refugium header tank?

I didn't want high flow through the sump, that was a result of wanting high flow out of the tank to carry suspended "crap" out of the maintank into the sump. the settling chamber is the second one. the inlet chamber "first" is about 6X6 and over flows over 2 sides to a 18X12 section, then through some weirs and into the return pump section. as for putting the chiller and UV on the same pump.. not a chance way to far apart flow requirments. All my equipment was in line, except for two pumps. so I had less heat contrubution than most. and what I didn't mention was I was also running another 25 gal tank off the same sump. the new one I am building will be much different with regards to pumps and locations. to me a sump serves to purposes, hide equipment, settle out junk, and add water volume.

One thing that we have to remember is when we have a sump system people tent to treat the water in it as different from the water in the tank, it is all one system and one large water volume, so in reality the flow is a mute point as the water in the system all gets skimes at the same rate no mater what the flow through the sump is, Unless you go with a ultra low flow then you are putting enough of a seperation to the system to actualy had different water qualities in your Sump than you do in the tank, not by much but if the flow is low enough there is a possibility, a fast water flow helps disperse/desolve/spread things more evenly and faster.

I guess the point is to think of your system as a system not two systems, the sump just give a remote option for hiding equipment not a seperate water system.

Steve