Mason,
Try running your diffusers only at night in the summer vs. all day. Diffusers off of an air compressor are really not aerators at all. They are mixers. Very poor for actually adding oxygen to the water. I think running them 12 hours a day would be sufficient and any plants or phytoplankton you have in the pond should produce oxygen during the day anyway.
As far as well flow into the pond, that will definitely reduce the water temperature if there is enough. The question is, is 25 to 35 gpm enough to do so in a 1/4 acre pond? My pond is only 1/10 acre and even though I pump in 45 gpm 24/7, I still get up to 65 on the surface in really hot weather. It's possible it's cooler down deeper, but I've never been able to get out far enough to do a temp profile without a pier or boat on the pond.
That said, your ground water is cooler than mine at 45 F. vs. my ground water of 51.6. F. That will adding some cooling power, but how much is the question. And if you have any shade at all, you have another advantage over me.
As far as aerating the ground water before entering the pond, the more saturation you get the better you will be off. However I'm not sure if you need to go as far as using a packed column like I do. Maybe cascading it over some rocks would suffice?
I often wonder if one could achieve close to 100 percent oxygen saturation in the well water, and then flow the water directly to the pond bottom (Pipe enters the pond on the bottom vs. being dropped in at the top), if that would sustain a cold water layer that has enough oxygen for the fish? Of course you'd have to forego the diffusers if you wanted to go that route. I've never tried it though. It seems the cold water would be dense enough vs. the warmer water around and above it to stay down.
I would also suggest you make your overflow to skim warmer water off of the surface vs. the cooler deeper water.
Last edited by Cecil Baird1; 04/11/08 10:27 PM.
