IMO & IME......I have a filter that has the bio-wheels and here is what I did. I took pillow stuffing and packed it in then I bought fluval ceramic bio-media and placed it on top of the poly-fil, then the bio-wheels. This is on a 55g and I don't have any issues, clear water. Although I do 50% weekly wc, once a month I take some tank water, during pwc, and swish the ceramic around to get any build up debris. Note: AFTER I WAS CYCLED, 1-2 a month I put new poly-fil in because all bb is on the ceramic bio-media....good luck