The two external pumps I use for circulation on this section are[FONT='Lucida Grande', 'Trebuchet MS', Helvetica, Arial, sans-serif] 1090 Coralife pumps. They run 90w a piece. I've been using two of these as return pumps from the main sump for a few years now. IMHO, it's a good idea to use multiple of the same pump if you're going to need multiple pumps. I have redundant parts and redundant pumps in case one goes out on me. Having two matching on the display returns means that I only absolutely need one at a time, although both are running at all times.
For flow on the system, I have the one 1090 running approximately 800 GPH almost as a closed loop from the cryptic fuge. Two others as returns from my main sump. Two MP-40's on the ends of the tank. That makes quite a bit of flow, but I'm considering one more MP-40 in the center back. Keeping SPS as thick as I want, I need serious flow, and I can tell by the polyp extension what corals are happy and what could use more flow. [/FONT]