It depends on what you want to keep. I have a 29g all glass with koralia 4, majijet 1200 and maxijet 400 + 200gph from aquaclear 50. that's about 1800gph. everyone is happy. it is a lot. other people have commented on that already. you should get 2 powerheads and face them towards each other. I think (2) koralia 2 should be ok.