75g Pump Suggestion

i see, 10acrewoods, you mentioned mag drive, and i searched for it and found the picture that looks like my current pump, so now i know i have model 5 which is 500gph

 

I'd say a mag 9.5 or a 1200, I run a 90g with a mag 18 that is backed off a little bit but I also use my primary return pump to feed my calc and po4 reactors

 

On my new tank I'm planning on only turning over my tank volume through the sump 5 times an hour about. Save on electricity/heat for one thing.

Pumping water through the return isn't the most efficient because of the plumbing headloss. I'm getting all of my water movement via in-tank powerheads. I don't know what benefit you get from going to higher turnover rates like 10x tank volume. Makes for noisier plumbing too, the more water you push down the overflow I believe.

Something to think about anyway.