Bambam is correct. I run 2 of the Voyager 3's in my 125. I started out FOWLR, but Bambam has "experimented" with different corals and what not in my tank to see what survives. Monti cap, Birdnest, Xenia, BTAs, and Star polyps seem to like the flow. Now, I have been thinking about upgrading to the Voyager 4s. They run quiet, are consistent, and reliable. Overall a great buy. Definitely a mid-range powerhead that is of good quality.