bio wheels=nitrate???

[tank_keeper_516]

I just read some1 say that biowheels, biomedia, and wet dry filters cause nitrates. I was wondering what the exact chemistry was on this because I use 2 penguin 350s (biowheels) on my 125 and I have 0 nitrates. The tank is 7 months old, has 80-90lbs of LR and about 75lbs of LS. I do run a seaclone 150, but I only clean it once or twice a week. Other conditions as follows
salin: 1.026-1.028
Ph: 8.1-8.3
alk: 10-11 dkh
Calcium: 440-460 mg/l
nitrite and ammonia stay at zero, I use seachems reef plus/complete and have excellent coral growth and pollyp extension. I do have some colerpa in the tank, but I'm sure its not enough to eat all my nitrates. So if anyone could help me out, that would be great.

[drummereef]

How long has your tank been set up?

[tank_keeper_516]

7 months

[bertoni]

Bio-wheels and the like do seem to contribute to higher nitrate levels in tanks. Phasing out the bio-wheels might help, if the stocking levels permit that. What's in the tank in the way of fish?

There are a couple of theories as to why bio-wheels can cause this problem. One theory is that they inhibit denitrification by converting ammonia to nitrate in an aerobic environment. At that point, there's no transport mechanism to move the nitrate to the anaerobic zone where most denitrification takes place. There are some papers that suggest that might be possible, but I don't know of any data on how much denitrification is done anaerobically in our tanks.

[drummereef]

7 months is a relatively short amount of time in regards to reefkeeping. Nitrates tend to build up over time and cause issues gradually. It's getting rid of them once it starts showing which is difficult. I agree, biowheels work essentially the same way as bioballs. They do a good job breaking down ammonia and nitrite but are not very efficient when breaking down nitrate. If you have enough live rock to support the bio load I'd get rid of them.