I just put a hydor pico evo-mag powerhead, the 300gph in my 10 gallon nano. I have it in the top left rear corner by my skimmer outlet, and it easily pushes from that side to the other and back. I love it and my corals seem to also!
It has an adjustable flow, so you can slow it all the way down to about 50gph, and the end rotates so its not always flowing in just one spot... almost like a wavemaker without the shutting on and off