I have a 130 gal frag tank that needs a return pump. How many GPH does it need to be? The surface of the sump water will only be about 3' feet below the surface of the tank its self.
Can't really suggest one but do some comparisson shopping on specs and electric consumption. At least that's how I went about it.
Some will come along with a better answer I'm sure
The general rule of thumb is to run 3 to 5 times your tank volume through your sump. Some guys run a lot more but I have always stuck with about 5 times.
Make sure you account for head loss.
If you are running 1" return pipe you could probably get away with a mag9.5. But, you may want to get something that pumps that much with a lower wattage rating. That's been my only beef with mags is the electrical consumption.