plumbing sump/refuge

[daddy01]

Hi,
I have a 30X12X21" tank set up and am adding a 10 gal sump/refuge underneath (hopefully) that has two chambers one with macro algae in it hopefully to stabalize nitrates etc.
I have purchased a CPR overflow box for the main tank, and a mag-drive model 2 utility pump (250 GPH) for return.
Is this an overkill situation? The return system is only 36 inches from main tank to sump. I am contemplating using 1" PVC for CPR overflow, and 3/4"(?) PVC with elbows for return, will the elbows create to much back pressure?
Jim