my few comments in addition.
the Mag pumps are great for the price, but tend to be a bit lound, and the get real
hot.
check out little giant pumps, quiet one pumps, and iwaki pumps.
these are what are used in the tanks where "people want the good stuff"
and as mentioned, dont worry about moving that much water from the return pump.. make it up in your flow (as opposed to turnover as dave mentioned)
and as far as over all flow, my minimum recommendation is 15x, preferably 20x.. 10x is a bit low
IMO
