I took it out and the bearings spin freely. I took out the filter cartridge and it didn't help. I can spin it with no resistance while it's in the filter. It *might* move about 1 cm every 10 minutes. Should I get a whole new filter? The tank is established and the cartridge is not new so if the wheel wasn't working as a bio home would it matter since I have the other sources? I really don't want to buy a new filter, although I have had this one for a while.