I have a small 9 watt turbo twist on my 85 gallon system and it seems to work well. (knock on wood) I haven't seen any diesease or bad stuff in my tank. I only run it for a little while during the day time. The UV along with the pump are on a seperate timer. The pump is on one end of the sump, goes through the UV and then dumps on the other side of the sump bypassing the fuge so I don't believe anything will get sucked up and die lol...