update: absolutely thrilled with results. Thanks to all!!!

Wow, so we ended up installing 2 homemade solar heating systems and a cover for our old, deep, big cold pool in San Francisco. We are thrilled!! The highs have been around 68-72 for the last week or so, but sunny. The pool stays around 83-85 degrees! The family uses it constantly, even my wife who almost NEVER gets into ANY pool...

I uploaded some videos to youtube if you are interested (parts 2 and 3 are the new system). Thanks to all in this forum for advice and tips!





Alex