I just wanted to add this: with the FX5 by it's self, my water perimeters were always perfect, but the water was never crystal clear. It was always slightly cloudy. I added a Magnum 350 to the tank with the micron filter to act as a water polisher and now my water LOOKS as flawless as it tests. I also have an AC110 on the tank just because I had it laying around. I use it for extra mechanical and if I need to add chemicals, I put it in the AC110. Right now I'm running Zeocarb in it; again just because I had it laying around.