I have one of these on my 8 foot tank. I am still up in the air on what I think of it. My understanding was it would create a nice even flow. It does an excellent job of creating flow, almost too much power. I run it at 30 or 40 percent. At this power I had to move some of my corals around as the flow on the same side of the gyre is quite strong and most corals did not like it. Anything above 60 or 70 percent it starts to make a bit of a squeal out of the pump. Nothing crazy but noticeable and more than I expected. All in all as far as flow goes it is very capable. I crank mine up every so often and it stirs everything up so it can get filtered out. However, as was mentioned by a previous poster, this afternoon my Fromia Star was found sucked to the bottom side.......... makes me wonder if I made the right move, time will tell. Also, I would go for the larger one and keep it turned right down, I would think this would be easier on the motor than running a 35 watt at a higher percentag.