"I am using my H.O.T. Magnum for a 55 gallon show tank, so I have 5 times the cleaning power needed. I have never had a problem with ammonia, nitrates, or nitrites. My water is crystal clear all the time. The only thing to pay attention to is when you take it apart and put it back together make sure you fill it to overflow before you seal it or it will make alot of noise, this is a very easy fix. Great filter!"