So I'm plugging away at this, and unled I'm reading Bill's above response incorrectly, it seems aeration would be beneficial at Stately Gaffney Manor.

found this chart http://www.vertexwaterfeatures.com/aeration-lifting-rates

And assuming my half-acre pond at 5' deep contains about 980,000 gallons, it appears with two vertex disc diffusers, I can turn my pond about every eight hours at 2 CFM. It appears the vertex discs like 1 CFM each.

So, my new questions are:

1. Is my math right? I was an arts major.
2. If it is, would I do better placing the two diffusers in one bank, or place the diffusers a nominal distance apart, say 75 feet? What's more effective? Lots and lots of bubbles in one area, or just lots of bubbles in two different areas?
3. When I'm spec'ing out the pump, how much line loss should I cook into the recipe. I have some 3/4" PVC left over from an irrigation project, and I'm thinking about using it to get the air to the edge of the pond, then going with weighted tube in the water, UNLESS ;-) someone convinces me that running the PVC in the pond is a good idea. I'm thinking it isn't.
4. How QUIET are y'alls compressors? Will I have to be concerned about waling the neighbors?

Thanks for your input. And if I'm completely out-of-whack on this, please let me know.

Mark