You are not really supposed to clean or replace the bio wheels. If there is noticable build up on it then rinsing should be done and then figure out why the build up. If you rinse it then a quick rinse and not a scub. The bio wheel is where you beneficial bacteria grows that filters your tank. The reason it spins is that the bacteria grows, multiplies and does best with the mixture of air. There are many reasons that it can stop turning. The most common is the water spraying on it causing the turning is hitting it in a way that doesn't cause to go clockwise or counter clockwise. the second most common is the actual fittings where the bio wheel sets into the filter. these can be replaced by contacting the manufacturer and will cost almost nothing. check these fittings and that the pegs on the bio wheel turn smoothly and its not getting caught up there. Alter how your water hits it. This will probably cure your problem. Very rarely is it the bio wheel itself and therefore replacing it won't usually work. Good luck.