I've just never cared for the UV myself (personal preference). I had one at one point, and although I did notice I had to clean the tanks glass less regularly. I also noticed that my pod population wemt down dramatically. I'm sure there could be other reasons but at the time I didn't have any fish that was a strictly pod eater. Once I took the UV off my population started to thrive again (you can really nitice at night with a led flashlight). Maybe coincidence but I just prefer to stay away from UV for my reef tank. They do work great for a pond though if you have one.