confused...skimmer and pump?

So I have a 220 gallon tank cyceling right now with a 60 gallon sump, I am buying a AquaC EV-240 Protein Skimmer off someone for a good price. He is also selling me a mag 12 pump. All the sites say it needs a 12 or 18 to run. So my question is what kind of return pump do I need? I would assume I would need a mag 12 to match the skimmer, but on a few web sites it says the skimmers gph rate is 560, and the mag 5 pump gph rate is 500. I have a mag 5 pump so I wouldn't have to buy a new one if this is good enough?





So to sum up do I need a mag 12 or is a mag 5 good enough?