I recently bought a Coralife Turbo Twist 3X 9W. I didn't want to cut the lines on my Fluval filter so I am running it straight off a power head. I'm sure it will work off the output though if you wanted to set it up that way. As for how it works, my 75 gallon tank has had green water for weeks. At times, I couldn't see the filter output or intake on the back of the tank. And that was despite the fact that I was doing daily 30% water changes. I had done a water change the morning that I set the UV sterilizer up so the water was at least clear enough to see the back of the tank. I started it running Sunday afternoon and my Monday afternoon when I got home from work, my water was crystal clear. I love it and plant to buy another one for my goldfish pond outside. I got mine online at Big Als for somethin like $77.99 plus shipping.