Biowheels.. good or bad?

[ncosper]

I have heard many different things on the pros and cons of biowheels. I'm most concerned with them producing nitrates. How much of this is true and how big of a difference do they make in one way or another?

 

[DarwinTheDog]

I would not recommend a Bio-Wheel for a reef, if that is your intent. While a Bio-Wheel is a very efficient biological filter in terms of aerobic activity (converting NH3->NO2->NO3) there is no anaerobic process with this filter. The result is a filter like most biological filters that is very good at converting ammonia to nitrate. While in a fish only system nitrates might not be problem (can be diluted through regular water changes), in a reef that is a different story.

Your best bet IMO for a reef is using some form of the Berlin method in conjuction with a deep sand bed. In the Berlin method the live rock in essesence is your biological filter that host bacteria that converts NH3->NO2->NO3. The deep sand bed can promote the development of anaerobic bacteria that convert the NO2 (nitrate) to N2 (nitrogen gas that can be diffused into the atmosphere). So the DSB can help keep NO3 to a minimum.

So the short anwser to your question is Bio-Wheels are good biological filters, but they would not be MY recommendation for a reef tank. Remember their are many different opinions and approaches to reef keeping, but that would be mine.

Best of Luck!