My local pool store was running a close out sale for Sun Grabber pool heaters. They were $75 each for 2'X20' rolls of solar collectors. I got two of them to heat a small pond I built a couple of years ago. It is about 10,000 gallons. I was able to heat it from 65F to 80F in two days! I'm using a 2 GPM fountain pump and various fittings and pool parts as well as a pond filter I had left over from another project. For $200 I got a solar collector that uses 80 watts of power to pump 8.2KW of heat 12 hours a day this time of year. My collectors are flat on the ground right now, but soon will be elevated for greater efficiency. This should allow me to put some breeder tilapia in my pond shortly. The pond is now 80F with average temps here still in the mod 60's and torrential rain falls.

I'll shoot some pics tomorrow of my muddy setup, but the results are beyond anything I expected. At current power rates of 10 cents per KW hour, my setup is saving me $10 a day in electrical cost. How many things do you know that give you a break even in 20 days?