Hydor Koralia nano pumps are cheap and effective. For FOWLR, you nead at least 20 times your volume in GPH, and reef, at least 50 times your volume. It's better to have many pumps because rocks stop circulation if you use say only two. I'd use 4 pumps for FOWLR, 425 gph each, 6 for reef : 2x550 GPH, 2x425 gph and 2x240 gph. Like I said, if your rock works doesn't block flow, you could use less pumps, and use more powerful ones.