Has anyone heard of a temperature rating for vinyl liners? I have an inground vinyl liner pool and my pool supplies store (also was the builder) insists that I need to keep my temps in the 80s or lower to keep from ruining the liner. I'm having a hard time finding anything to support that online. I like to let the temp get up in the 90-94 range for therapeutic reasons (bad back from football). My initial thought was that the water temp can't hurt it more than the sunlight all day -- but he's been building pools for 40 years, and I'm just a regular dude making a guess. Thanks in advance!