Originally Posted by peckhead
would throwing a bio wheel in a sump or overflow box benifit a tank at all?
It would be redundant. There is nothing that a biowheel grows that doesn't grow on LR, bioballs, or even substrate and tank walls. So in most cases, the biowheel is removed because it is unnecessary as part of the biological filter. Not in particular because it is growing directly harmful bacteria.
When these objects - bioballs, biowheels, and yes, even live rock, become overwhelmed with detritus, nitrate problems arise.
Ugluk - Yes, people do many modifications for these hang on filters, including making them small refugiums. But I would propose to you that if you have a tank with LR (and it is not a predator tank), and have lots of circulation in the tank from power heads, then you may not need these filters at all.
HOWEVER, the filters will pull up, as they were intended to do, particles, excess food, etc. Normally trapped in a filter pad where it can easily be removed and cleaned, this food and gunk will then be trapped in the live rock rubble. And this too can result in problems.
