Josh - One pump could just run the locline returns as a closed loop, but then that pump would have to have a separate drain line from the tank. I did drill two 2in. drain holes in the back of the tank which I realize is way too much for only a 75. I could just reduce one of them down for the closed loop.

I was afraid that it might be too much flow through the sump, but if I only had a single large pump, it would still be as much flow through it. So the closed loop idea would probably work better. Also thinking of using SQWD's on the locline returns to alternate the water flow so it is not a constant flow in one direction all the time.