I'm setting up a 29 gallon with a 15 gallon sump. I have ordered 2 SCWD's from Inland Reef. I was thinking about a Mag 9.5 to drive these. Will this be too turbulent for a 29 gallon tank? Obviously I can put gate valves on the SCWD's but will too much back pressure hurt this pump? My sump will be about 4 feet below the top of my tank. Thanks for any input.