Yeah I noticed that the tank gets cloudier with water changes the longer it goes with out a change the clearer it seems to get to a certain point. I just upgraded to two rena xp3s from two emperor 400 so I have all 4 running right now, so I'm sure when the xps3s get cycled it will help allot. How would you run d.e. in a aquarium?? I own a pool company so I kno all about filters for pools but iv never heard of anything like that being used on as fish tank.