Let's talk about bio load.
 

So looking at skimmers, most are rated for different volumes at different bioloads.
How do we measure that? I mean, quantitatively, what's a medium bio load? Or heavy? Or medium light?
Compared to what?

How do you gauge your bioload?

Good question. I think I have a heavy bit load with 7 fish in my tank but there all small basslets and two fire fish. So is that low compared to wrasses or tangs

No idea. And that's weird, cause I usually have an answer, even if I make it up :)

This time I got nuthin' lol

I think I have a medium(ish) load. On the light side, but I feed heavy. Sort that one out!

Maybe bit load should be based on amount of food you use.

Do we weight it per gallon?

I have a 6" angel, a 4" tang, 8 Bartlett's Anthias (2"), a Leopard wrasse about 4 inches, 2 clowns and another anthias (Lyretail). 50 frags. 3 LPS various sizes. 40 snails. 2 abalone. Some sand snails.

107g of water, 50 pounds of rock. Give or take.

We call this medium? Heavy? Light? I dunno. I picked medium because it's in the middle :)

I guess a pound of food is a pound of poop regardless of how many fish

No, would depend on age of fish (is fish growing still?), temp of water (effect on metabolism, etc). A pound in is not a pound out. And sand beds complicate the equation. What gets retained in the sand vs bare bottom. What gets removed as solids in a filter sock if you use one?

This is complicated :)

I guess you would have to find a way to calculate the time it takes your tank to process a days waste. Having a number value to the amount of organics in the water column. You could turn a day into sections. 4 hours to process the waste is low 8 hour medium and so on.



But I'm not tgat kind of smart

Pretty confusing subject! I kinda thought bio load depends on how many fish you have. Sea_Horse Fanatic or Anthony as some of us know him has a 160 g DT and lots of fish and I know he considers it heavy bio load, hopefully he'll see this thread and chime in and shed some light for us. :confused:

I consider my bioload medium and the skimmer I have is "realistically rated (TM)" for 250gal or 180gal heavy bioload. It seems to do ok and I've never not had algae (except for that one time) so it does as well as I expect it to.

I generally gauge my bioload on fish type and size. Tangs eat a lot and crap a lot and I have a "enough" of them so I'd consider myself medium bioload leaning towards heavy-ish.

Interesting question. I also am interested in how people relate their bioload to skimmer size and "over skimming". Is this even possible?

My theory (as if anyone cares):

Testing of bio-load has to be through titration but instead of adding drops of some chemical, you have to keep on adding fishes till you see (whichever comes first):

1. Sudden growth of algae
2. Sudden deterioration of water quality
3. Do water change more than you would like to

When any of the three results matches, you have a heavy bio-load. Small bioload is the point where you don't see any fish in the tank (or you are an irrational environmental activist) and medium would be anything between small+1 and heavy-1.

I don't think you will see a sudden anything. I think of it as more gradual thing. It is a biological system, and, depending on your rock, sand, reactors, etc you may or may not be able to process a certain amount of fish waste. The bacteria will adapt and multiply to the point where they encounter a limitation of some sort (usually carbon). If you supply that, they will continue to grow to match the bio-load.

I also think of corals as consumers of nutrients, rather than adding to the bio-load. Am I wrong?

While they use nutrients they do not really remove them from a system just process them and get rid of what's not used, this may be food for other life including other coral . Certain things can not get processed out and eventually need some sort of export out of the system.

As for the size thing , its not always the biggest animals with largest bioload , snails , urchins and sea hares tend to do a lot of pooping lol

I would bet a sea hares waste is ten times as much as fish three times it's size.

So then, how do I estimate my bioload? Good question, huh?? :)

I always just get a skimmer twice rated my volume size , seems to work well lol

bioload
 

i have always gauged my bio load on type of fish and how many I have and size and feeding .I have a 90 gal tank and I think I am pushing the heavy side of bioload I don't think theres away to measure other then maybe skimate from your skimmer .I like the idea of a skimmer twice the size or close to more then half of water volume . just my two cents worth

Use a calculator..

http://aqadvisor.com/AqAdvisorMarine.php

Almost had it there :) Most fish missing from list.

Ya, works well. Guess there's no real answer to this :)

Way more complicated than I would have ever thought. After doing some reading the bioload also is affected buy amount of available oxygen, surface area (which is probably for oxygen) free swimming area and fish behaviour (sand sifters , schooling)

I thought you dont care about these sorts of things in the hobby. You are my idol for the LTFA method (and I am not kidding).

Not to mention bacteria of all sorts , these are a bio load often overlooked;)

lol! You're right, I don't really care, just thought it would be an interesting discussion. I'm looking at all kinds of skimmers that give different ratings based on bioload, and it occurred to me that there really is no measurable way to gauge this. Based on the thousands of responses, it's a tough question, or not many people are as curious as I :)

For me, get big skimmer, make big foam, remove big poop. Done job.

I read somewhere that skimmers, no matter how efficient will never completely remove all organics, there's a very small difference between the best & mediocre ones in that regard. I doubt that there'a 'formula' to measure bioload that will work consistently for any given person's tank. If a tank is overstocked & under maintained with respect to water changes, I doubt that even the best skimmer will keep up.

One would think that measuring nitrates & phosphates would provide some indication of whether one's bioload is exceeding maintenance or skimming performance. Or if one is battling algae issues. I'm stumped because if anything my bioload has decreased lately, hair algae issues I've had in the past are almost non existent at the moment, but I recently tested my water (after not having done so for many moons) and my nitrate reading was about the highest I can remember.... yet minimum algae issues & the critters including anemone & coral I have are doing well....

I think the best way is by food usage, more food the heavier the bioload, but this is complicated by natural occurring food in the tank, like algae that your tangs might eat and so on.

In the end though the only way to tell if your skimmer is big enough is to see if it is removing what it is supposed to by water quality tests. That's why traditionally we have always doubled the size of skimmer that we thought we needed.

Steve

The problem with doubling up your skimmer size is the removal of beneficial organism. This has been shown in tanks that use zeo or like methods.

what organisms are we removing exactly compared to their reproduction rate? are we talking bacteria?

ratings on skimmers vary so do we go by pump specs or by manufacture recommendations, and whats considered a healthy population to begin with and does age of tank play a factor?

im sure skimming removes lots of things including some beneficial bacteria , metals , phosphates and organics etc. alot of these id rather pull out then save , the amount of beneficial bacteria ratio to the reproduction rates it would take a long time to see an effect or complete wipe out, things added to the tank are going to replenish some of these organisms over time as well as the food sources and carbon we add, and new bacterias are always willing to take the role of old ones.

so overall ive always doubled my skimmer , i also carbon dose and rely on my skimmers performance to make it as effcient as it can be since i dont run filter socks or any other way of removing it.

ive often tied new systems into mine so its nice to have a skimmer that can handle a larger water volume and ive also been known to upgrade.
over the years ive had more issues of skimmers not performing rather then performing to well :)

I do agree with you. Just stating based on threads on zeovit forum. It's always been suggested to turn off skimmer while dosing and for few hours after. Also zeo claims that using needle wheel skimmer are to efficient. Pulling out the dosed bacteria. I do run a skimmer that's more than 2x the capacity of my tank, but only run it 16 hours a day.

yes there is , and which is one of the reasons i always dose down stream from the skimmer.

Another consideration is when setting up a new tank it skims a ton and as the tank matures the amount that is skimmed becomes less and less and that tends to throw a lot of reefers for a loop this can also be said for putting a new skimmer in an established tank

But in the grand scheme of things I honestly don't think there is an accurate way to measure bio load it just comes down to user preference and past experience IMO

Over-skimming has nothing to do with removing beneficial bacteria, while such bacteria exists in the water column the amount of it compared to what attaches to surfaces in basically zero. Skimming removes bacteria about as effectively as water changes. Over skimming removes desirable elements such as potassium which can effect coral health. This can be avoided even with grossly over-sized skimmers by dry skimming rather than wet skimming and dosing to compensate.

In terms of zeovit the system is based on strong skimming, I remember previous versions of the guide actually stated you couldn't use a skimmer that was too large however that probably resulting in some using ridiculously over-sized skimmers meaning elements where depleted faster than they could be added. Thus the added note stating not too use a skimmer "too oversized" but you should still use an "over-sized skimmer". Also nothing official from zeovit suggests shutting a skimmer off during dosing, only to dose downstream of the skimmer in order to give the bacteria a chance to populate within the aquarium (same for the reactor mull).

Dissolved oxygen, actual vs. ideal/theoretical

Charles

Near impossible for a hobbyist to measure, but that might do it. Perhaps redox values instead?

I've though about monitoring orp but after all the research I've done its about as important as ph

This isn't exactly true... For example, systems in which organic carbon is dosed remove a lot of bacteria via foam fractionation (skimming). This is actually the primary way in which such systems control phosphates; by removing the bacteria that bind/use/consume them from the aquarium. Also why skimmate colour changes significantly when dosing carbon (ethanol, vinegar etc). Zeovit systems also remove a substantial amount of bacteria by skimming; when the 'mulm' (basically bacterial biomass) is shaken and released, whatever isn't immediately eaten or otherwise used by the inhabitants is skimmed out.

Why is dissolved oxygen impossible to measure? There are dissolved oxygen meters. I have one.

Meters are rare items owned by hobbyists. And titration kits don't work well at all.
Not impossible, but not something that is useful, therefore difficult to justify a meter.
Hobbyist meters are also likely not maintained well, so the value could be way off.

It was useful for me to determine that my tank was overstocked with low DO at night. Without heavy aeration turned on at night, my DO levels were lethal to oxygen demanding fish whereas another reefer who borrowed my meter had a lightly stocked reef where the DO hardly dropped at night. Even with aeration at night my DO was low due to the high bioload.

Here's an affordable one
http://www.amazon.com/Milwaukee-Econ...JCANWD2MRRMSER

Still $150 bucks! I know so many people that won't splurge on a new refractometer for $40 :) And that's bit more useful :)

Some reading for anyone who's interest in bacteria numbers , removal and what carbon dosing does to certain bacteria.

http://www.advancedaquarist.com/2011/3/aafeature