Look at the via aqua seres pumps, sen and Mag drive pumps.
I run a via aqua 3300 on my 55 fowlr
and I have more then enough flow I actually have it cut back some. I was running a Sen 700 on my 125 reef with a T return to two hang on returns and that was good flow I then broke the shaft cleaning it so I now have a Via aqua 4900 and it works very well. I would like to have a Sen 900 for the extra flow but the others are great.
Look them up on the internet and they have a flow chart and what the GPH
rating is for each.
The Via Aqua is a reliable pump, when the power goes out there is no need to bump, bang, spin anything like with some other PH
If you run the return back with hose inseted of PVC
you will not have to worry about the elbow issues. A miracle sells a nice hang on return that the hose just slids over and a hose clamp. Very cheap, easy setup
are ment to be in the water not out. They do make return pumps designed to be out of the sump but you need to drill a hole in the sump to run them. These type pumps run more $$$ also.