I installed my solar heater 5 years ago. It's the best investment I could have made for my pool.
With the help of a solar cover that I always put on at night, my pool sticks to 90F+ all summer long. The kids and their friends love it and they spend all their time in the pool instead of playing video games.
here's the installation thread: solar-panel-installation-pic-t5823.html
Now 5 years later, the dreaded first leak appeared. The leak is not with the panels themselves, but rather with the rubber coupling between 2 of the panel headers.
Oddly enough it doesn't leak under pressure during the day. Instead it leaks when the pump is off during the night. At this time of the year, we still have very cold nights (40F) and I suspect that the panels contract because of the cold, causing the coupling to leak. I watched it early this morning and within 15 minutes of the sun hitting the panels, the leak completely stopped.
Now I need to find a replacement rubber coupling. The dealer that sold me the panels is long gone but I think those are the standard plumbing rubber couplings. I just need to make sure they are UV resistant.
While inspecting the panels, I also noticed that the constant expansion/contraction cycle caused the couplings to "dig" into the underlying roof shingles. I'll install some sort of wear plate to avoid further damage. I saw this example on the "hotsun industries" site: