I use a rotary vane compresser that is 1/4th hp that puts out about 4 cfm to two diffusers in a pond that is similar in shape to your pond and only slightly larger. My max depth in that pond is 9 feet. It has served me well for two decades.
Don't be afraid to buy the components separately to save money. Be wary of overpriced turn key systems.
As far as a fountain or surface aerator, unless they pull water from the bottom of your pond they won't do your pond much good, but look pretty, cost a lot, and waste power.
Last edited by Cecil Baird1; 05/31/14 09:31 PM.
