Sorry, I kinda replied to the wrong post.. But I would agree the sun is brutal on the softest part of your pool.
Just my 2 cents.. I own a Intex pool and in the middle of the third season our liner turned brittle. Along with poor chemistry and the sun it was toast in my opinion.
Some background. We disassemble the pool at the end of the season and store it. Our liner always seemed to have a wrinkle or two so I tried to preclude that by adding another paver to the upright frame. At first it appeared that was the hot ticket but a rip developed. My point here is we limped through the rest of the season with about $40 worth of patches. The patches are quite effective, at least on a Intex liner. They adhered well but of course were not as strong as a good liner. I had the buttress/reinforce the outside of the patch with a 1x4 to support or it would fail.
At the end of the season when we went to drain the pool I allowed the sump pump to float down by its own weight and it gently touched the liner and poked a hole in it.
Like I said, my opinion, Poor chemistry and the sun.