+1 north. I have a 1200gph overflow box with a 1200gph return pump, and I highly recommend putting a ball valve on the return line to control it.
Restricting the flow to the pump will ruin it faster
What size sump pump for a 300 gallon tank?
turbo sea 1740p?
Wow, totally misread your post, I thought you were asking about the sump. Your return pump should match the flow rating of your overflow plus whatever you estimate for head loss
If your overflow box drains 400 gph for example, you'd want a return pump rated for 400 gph at whatever head rating you need