Not sure on the size issue. I have a double membrane diffuser on a pump very similar and it does a half ac pond very well and I think I have enough cfm to cut back on the double and run another diffuser but for me it would be way over kill. It will need an exhaust, pressure gauge, pressure relief valve, and plumbing . I am pretty sure this pump does not need a starter*(capacitor) and is direct wire 240v. My pump sits 1100 foot from my pond and has been running for two years(seasonal 24/7) I will post a picture of my pump later today. PS ventilation and a blower fan are a must for the pump life.

shoot'em in the lipps