I'm planning on buying a used 55 gallon tank, and the person selling is also selling their equipment. He has a Penguin Biowheel 330, and I was wondering if anyone could tell me if this filter is good for a 55 gallon, or should I not bother and just buy my own? Any recommendations? Also, what is an under cabinet filter? Someone else selling a 55 gallons said they have that, but I'm not sure what that even is.... Thanks! 8)