Ok, I think the trompe system is out. Very cool, but I don't think I'll get enough air.

Quarter acre brought up a point about the drain pipe washing the aeration back out of the pond. Which I hadnt thought about, but i think would happen with any kind of aerator, unless I put the diffuser in the drain pipe, which I was not.

The Cecil Baird idea is cool but it sounds like it involves pumping water. I'm trying to stay away from running electric to the pond.

I realize in my original post I just said compressor. I was looking at a compressor meant for a windmill, which they claim operates, minimally I'm sure, at as low as 3-5 mph winds. Which tells me it spins fairly easily. My drain puts out approximately on average 1 gallon per second. 60 gpm. My math tells me, I'm no engineer this is probably wrong. On a 5 foot waterwheel, I would have 1200 foot pounds per minute, or 20 pounds per sec. Which if geared right, I was thinking belt drive. I could spin the compressor at a decent speed.

And I may not even NEED additional aeration, but I figure it wouldn't hurt if I was planning on using beneficial bacteria to help clean up the muck, and figure the fish won't mind either

All that being said, I still enjoy hearing other ideas from everyone. I've learned a bit already.