The "800" in it's name is the maximum gph the overflow can handle. So you want a pump (minus head loss) that is less than 800 gph OR at least controllable so you can turn it down. If you wish to go with an AC pump, Danner MAG pumps are bulletproof and last forever. A MAG 7 would work just fine. That said, my preference would be a DC controllable pump, and you have a number of choices. I personally would be looking at Jebao 4000 or 5000. Note these pump designations are in liters per hour, so that calculates out to 1057 and 1321 gph, respectively. Again, these pumps are controllable so that's why you pick one that is greater than what the overflow can handle and simply turn them down. This way the pump isn't running flat out....I want to think the pump lasts longer by running at a slower speed.