[Myka]

The magic number through the sump for a reef tank is 6x turnover per hour which allows the entire water volume to be processed approximately 99% in 24 hours. Anything much more than that will only achieve washing of microbubbles to the display tank (not pretty, can irritate corals). 6x through the sump will provide the protein skimmer with the right amount of new water to be as efficient as possible. The skimmer can only process so much water, so washing a bunch of water through the sump real fast doesn't help the skimmer, and just wastes electricity. Some people argue faster flow when they use filter socks, and say the filter socks process more water with higher flow. My argument against that is if the socks can't keep the tank clear with 6x turnover then the tank is probably overfed, overstocked, or has poor circulation within the display tank.

For SPS I like around 60x turnover just with powerheads, for LPS 30x turnover is good. Some SPS tanks will have over 100x turnover...I have never tried that much. For a mix tank, 40-60x turnover is good...have areas of high flow and areas of low flow and sort the corals accordingly. Try to have lower flow near the sand (use smaller powerheads lower in the tank) where the LPS will be, but make sure you have enough down there that detritus isn't settling on the sand.

For a pump, add the display tank volume with the volume of water in the sump. Say about 85 gallons total. Multiply that by 6 is 510 gallons per hour. So pick a brand, and pick a model that is close to 500-550 gph at the head height of your tank (measurement from the pump to the highest portion of plumbing in the return line). For this size tank Eheim are great pumps, and they just put out a Compact series which are cheaper. I don't mind Quiet One pumps, but they aren't as quiet as their name suggests. Mag Drive pumps are loud, and I would not recommend them. Poseidon are external pumps and are very good, dead silent pumps, but are becoming harder to find.