For my closed loop:

two inlets
3.5 - 4ft rise
tank: about 70 gal (Corner)

Have a Mag pump for my return but on the closed loop was going to have one feeder line coming into the pump and then the line going out to a sqwd and then that to the two inlets.

The return will be a seperate inlet (3rd) from the Sump/Fuge.

So all this pump is going to do is circulation for the loop.

Looking at the
Little Giant 2-MDQX-SC - 640 GPH at 3'

or the

Mag Drive 9.5 - 800 GPH at 4'

The little giant is more expensive and has less GPH but is truley an external pump where the Mag 9.5 has more GPH and is cheaper. Can the Mag 9.5 be used as an external pump????

Which pump?