Pool winter cover is "melting"

[JaceTheAce]

One side of my 18' pool cover appears to be "melting". This is not happening on the entire cover but only on one side, and only where it's _not_ touching water. Anywhere it's touching water is fine. The cover is GLI's top-of-the line cover and it's only been on the pool for ~2 months. When I winterized at the end of October the chem levels were perfect _except_ I winterized 4 days after shocking and chlorine level was still at 13ppm. Yesterday I peeled back the cover and inspected the vinyl liner and re-tested chem levels. The liner looks fine with no bleaching or visible damage and chem levels are still perfect but the Chlorine level is now down to 4ppm.

Has anyone seen anything like this before? Should I be worried or just keep duct taping the holes until spring?

 

[JamesW]

My pool is burning

My pool is about to go up in smoke, literally! Last week I noticed my pool cover was burned. I assumed it was from the leaf embers that might have blown over. Fast forward a few days and I can see it getting worse. Today the wife calls me out and says the pool is smoking! Sure enough we get...

www.troublefreepool.com

 

[RaleighDawg]

I’d walk near there at different times during a sunny day and seeif you feel a heat beam coming from a window. Those double pain windows reflect the light as a beam that will melt hard plastic. i had a plastic slid in my back yard that started getting deep grooves cut into it. about the same area that my grass always died each summer. then noticed it was hot while standing near there.

it finally explained so many things going on in my backyard. plants that seemed to always die every year next to ones that thrived, lines of dead grass across the yard and the melting plastic.

Recently i have been trying to figure out how to harness it to add heat to my pool throughout the winter. The solar cover works great, but can only help so much when it is in the 20’s at night and i’m trying to keep the pool at 85. Wish there were more choices for winter solar covers with more insolation properties.

I saw an article about it years ago that some fires were caused from the reflected light.

Figure you could add film to the window to reduce it, but not sure.

 

[JaceTheAce]

@JamesW & @RaleighDawg: Thanks for the replies! I started suspecting it might be reflective solar damage when the duct tape I put on the holes also melted. Yikes. I then stepped out to look at it at various times during the day and, viola, you can see the reflection from our big South window and the melting pattern follows the sun as it moves across the sky:

 

[borjis]

Wow.
That reminds me of a new casino in Vegas a few years ago. Reflective mirror glass was focusing intense sun beams in areas of the pool. A few folks were injured. Can't recall how they fixed it.