Well now you have created interest for me on this topic so I am off to look into it. I have never used a bio-wheel so my opinion is purely speculative.
But, if you were using an Aqua Clear HOB
the water flows up through the sponge, carbon, bio-balls or whatever media is there and the bacteria colonizes on the sponge etc.
Does a bio wheel have to be turning for it to collect bacteria? As long as water is flowing through it it will not hold bacteria?