what replaces the beneficial bacteria on the bio-wheel in the power filters
Nothing. The bio wheel is an extra source for bacteria to grow on.
That is the really neat thing about Bio-wheels. They should never be replaced. As long as they are kept running in a working tank the bacteria should grow and live in a perfect environment unless chemicals are added to the water that would kill them off. The only other way to seriously disturb the Bio-wheel is to stop it from running for over 30 minutes or so, which would tend to disturb the bacteria on any medium. The reason I love them is the disposable media can be changed or rinsed or whatever and the Bio-wheel doesn't even have to be disturbed. They get to looking gunky but the gunkier the better for bacteria growth. Never rinse a Bio-wheel, you will set your tank back. The prefilter should take care of debris and keep you from ever having to deal with anything else.
ya i knew that about the bio-wheel but you should rinse it once in a while in used tank water only when there is so much gunk on it that it is not spinning well
Yep you can do that.