Bio wheels
I have 3 of them in various sizes in relation to my tank sizes....I find them excellent filters. And as said in the replies to your original post the wheel only needs to be changed should it get damaged. The only thing I do to mine is to rinse out my filter pads in a bucket of tank water when I do my water changes to clean the gunk off of it. This way you don't kill or disrupt the biofilter and the beneficial bacteria stays alive and present. The only issue I have with them is occasionally one of the wheels stops spinning, this cane be caused by a couple of reasons I have found, 1. the filter pad has plugged up with debris or slipped backwith the water flow thru it and is touching the wheel. Or the filter pad is plugged up with gunk and needs to be cleaned. Or the spindle on the end of the wheel has stuff on it and needs to be wiped off, all very easy fixes. If you find a wheel stopped you can lust lift the media pad up a bit to allow the water to flow freely around it and check the pad for any obstruction.
HTH
DF
HTH