FOWLR

[discretekarma]

Does a FOWLR tank need power heads? I have two Hydor 1200 gph power heads in my 100 gallon tank. I just got a 180 that I am going to make a reef tank and leave the 100 gallon as a FOWLR. I am trying to decide if I should take only 1 power head out or if it would be ok to put both power heads in the reef and leave just the 2 fluvals in the FOWLR for current.

 

Thanks so much.

 

Should this be moved to the New To The Hobby section or is it ok here?

[trble81]

Flow is always a good idea. It'll help with keeping your nitrates down (no dead spots and keeps stuff suspended to get picked up by protein skimmer or whatever). I think the general rule is 5-10 X your tank size per hour (so for 100 gallons, you want a total of 500-1000 gph).

 

[jason the filter freak]

I would say you most certianly need powerheads for a fowlr.

[Rascal]

Flow is always a good idea. It'll help with keeping your nitrates down (no dead spots and keeps stuff suspended to get picked up by protein skimmer or whatever). I think the general rule is 5-10 X your tank size per hour (so for 100 gallons, you want a total of 500-1000 gph).

 

 

It also helps oxygenate the water and off-gas CO2 to stabilize PH, and gives your fish "exercise" (don't ask me for any sources on that one, I pretty much made it up ). Seriously, though, these fish didn't come from ponds. What size Fluvals are you talking about? Assuming 404/405 (225gph ea) x 2, I think you will need to supplement that somehow. 450 gph total in a 100 Gallon tank doesn't seem nearly enough.

[discretekarma]

They are Fluval 404's. I have a Hydor Koralia #4 in there now and it seems ok. i haven't added any fish to that one yet.

 

I didn't understand at all what you are saying about off-gas co2. What does that mean?

[Rascal]

They are Fluval 404's. I have a Hydor Koralia #4 in there now and it seems ok. i haven't added any fish to that one yet.

 

I didn't understand at all what you are saying about off-gas co2. What does that mean?

 

Off-gassing just means when the CO2 which is dissolved in your tank water gets released into the air as a gas. Here's how it works and why it's important. Everything in nature tends towards equilibrium, right? So if the air has less CO2 and more O2 than your tank water, the water in contact with the air will release some CO2 and gain some O2. The more molecules of water that come into contact with the air, the more opportunities there are for this to happen. The more flow (also called "turnover" you have in your tank, the more water will be exposed to the surface over a given period of time.

 

Why is this important? All animals respirate (sp?), which means they take in oxygen and metabolize it, and release CO2 as a result. If you have a lot of photosynthesizing organisms in your tank, this process can be offset while your lights are on, because photosynthesis involves the consumption of CO2 and release of Oxygen. When the lights are off though, CO2 levels can begin to rise. In a FOWLR, I would suspect you would not have as much of an offset because you won't have a bunch of zooxanthellae in there giving off O2 during the photoperiod. All you will have is a bunch of big fish breathing -- removing oxygen and giving off CO2. CO2 is acidic, so this will depress your PH.

I have never kept a FOWLR, but I know that low O2 content and low PH are not good for ocean-dwelling fish.

 

HTH

[discretekarma]

Thanks so much. That's a great explanation.

 

 

 

 

Off-gassing just means when the CO2 which is dissolved in your tank water gets released into the air as a gas. Here's how it works and why it's important. Everything in nature tends towards equilibrium, right? So if the air has less CO2 and more O2 than your tank water, the water in contact with the air will release some CO2 and gain some O2. The more molecules of water that come into contact with the air, the more opportunities there are for this to happen. The more flow (also called "turnover" you have in your tank, the more water will be exposed to the surface over a given period of time.

 

Why is this important? All animals respirate (sp?), which means they take in oxygen and metabolize it, and release CO2 as a result. If you have a lot of photosynthesizing organisms in your tank, this process can be offset while your lights are on, because photosynthesis involves the consumption of CO2 and release of Oxygen. When the lights are off though, CO2 levels can begin to rise. In a FOWLR, I would suspect you would not have as much of an offset because you won't have a bunch of zooxanthellae in there giving off O2 during the photoperiod. All you will have is a bunch of big fish breathing -- removing oxygen and giving off CO2. CO2 is acidic, so this will depress your PH.

I have never kept a FOWLR, but I know that low O2 content and low PH are not good for ocean-dwelling fish.

 

HTH