Best return pumps?

[Myka]

Mag pumps are great for mixing salt, but I wouldn't use them for a return pump. Iwaki and Eheim are both tried and true great pumps for that size tank. The Speedwaves are getting lots of attention lately, but I'm waiting to see how they perform longterm. They seem like a good option. I would shoot for 5-8x turnover if I were you so assuming you have about 15 gallons of water in the sump that's going to be 425-680 gph after head loss.