heating a small pool

[rastoma]

I see a lot of plans on Ebay for DIY heaters. Has anyone seen any of these DIY plans? Just wondering if there's any cheap and dirty ways to heat up my small 2200 gal. pool for the kids to get a few more weeks use out of it.

I haven't put in a therm. to check the temp, but our days are averaging 91F right now and low to mid 60'sF at night. With a smaller amount of water it doesn't old heat and doesn't heat well during the day so even at 90F outside temp, the water is still really cold.

I found this device on Ebay too that uses a garden hose to heat water from the sun. It holds the water until it reaches a certain temp then releases it into the pool and refills and holds it 'till it heats up again. There is a drain on the side of the pool that will take a garden hose, but wondering if there's enough pressure to push the water back up into the top of the pool of like a 100' hose. This valve/device is $20 which if it could raise the temp by 10 deg. would be great.