bio-wheels ... how are they bad in the long run ?

[harryball69]

i just read a thread that says canister filters and bio-wheels are bad in the long run.. ive heard about canister filters being bad if you dont keep them clean. can anyone explain the bio-wheel problem....?

 

[oscarinw]

I believe it has to deal with the issues that they don't provide for a 2nd step nitrifying process. The one that processes nitrates. This is why the best possible filtration can only come from rock and sand because they also provide low oxygen zones where the bacteria that can process nitrates thrive.
Also, in my experience, the bio-wheels will stick sooner or later rendering them useless at that point.

 

[harryball69]

thanks.. makes sence