Over three decades, there have been solar covers of mine that have lasted 18 months here in the AZ Sonoran desert, and some of those years they were on just about every day. The last two, each used during our swimming season, of course, were big-time losers, or were they? All were the 12-mil thick blue ones and bought through different merchants off Amazon running between $85 - $125. Granted, I was employed most of those years and didn't care about water chemistry and such and certainly didn't think I'd become a sort of amateur hydrologist in retirement. Although the quality of these covers has probably gone down, I doubt it, and the merchants I've complained to insist its not them, it, or the source. It's me, the sudden expert in all things, where a little knowledge is worse than none at all. Still, I can't believe the higher than normal chlorine levels I maintain during swimming seasons, have caused such abrupt deterioration, so thought I'd ask this favorite forum of mine. Is it average for a solar cover in the Sonoran desert to last five to six months? Thanks...Joe