A lot of people like the mag drive pumps.
I bet you can get away with a mag 3 pump. I'm guessing you'll probably have around 4.5 feet of head loss and the mag 3 will deliver around 230 gph at that loss which is right in line with the recommended 3x-5x turnover through a sump. I'd also use 3/4" piping or tubing even though the outlet of the pump is 1/2". It'll really help out on the head loss.
For your head loss I assumed a distance of 4 feet between your display water level and the sump water level. Another .5 foot of loss using 5 feet of 3/4" pipe, 1 90 degree bend and some other minor losses.
hth.
