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I have a Lifereef single and I love it. It is rated at 700 GPH, but that can be changed based on your return pump. Heck even if you left it full open that would turn your tank 19 times an hour. Plus if you ever bump up to a little larger tank you have a good overflow. Don't be too concerned about getting your floor wet. The lifereef uses a U tube, and it works the best. One person said they had never had a problem with theirs and I think they said they had it for 10 years maybe. All you need to do is drill a hole in your return line so if power does go out you will break syphon (SP?) Does that make sense? I use a Mag 9 on mine, but you could probably use a 7, but at 4.5 feet of head the 9 might be a better buy.
HTH-
Jeremy