I'm tired of replacing our blue plastic solar cover every season or two. Part of it is the hard water in our area... the bubbles on the underside just start falling off. I can tell it's time to replace because every time I take the cover off, there are 10 - 15 new blue bubbles left in the water. Is there a better method out there? I've tried the chemical option, and it didn't seem to work very well. I've seen the solar rings, but not sure those will be much better. Is there something that's not made of plastic that will last longer than a season or two?