Howard,
Do you have any numbers on what the system is capable of doing? If we knew what the system could produce in terms of heat, knew the size of the pond, and your average winter temp, we could probably make a reasonable estimate of the effects on the water temperature of the pond...my friends like Theo and Burger would eat that up
(heck me too)...but I'd guess unless the pond is very small, the effect of a solar heating system will be negligible on the overall pond winter water temps and because of mixing there would be minimal area of warmer water.
Now if you could isolate the area, actually use a swimming pool, you might be in business, again depending on the output of the system. Heck, I threw in a hot tub for the cause...the least you could do is dedicate a swimming pool.
