The instructions that came with my Penguin say that even if the wheel is turning very slowly or irregularly, it's still working and you shouldn't replace it or remove it, and the only part of the filter that needs cleaning is the inside, the bio wheel itself shouldn't even really be rinsed unless it's absolutely necessary. The output is not nearly what I'd like it to be in terms of water movement, which is why I use the Penguin in addition to filters with a higher flow rate. The bio-wheel is home to millions of bacteria, unless there's a real problem with it I wouldn't recommend removing it, but you might want to add another filter or powerhead to get the water circulating more.