What is a good solar cover for a swimming pool?

Check with your local swimming pool retail store. Most solar covers are made in standard sizes (rectangles) and are constructed like "bubble wrap" material used in packing boxes. You trim the material to fit your particular pool. It simply floats on the surface of the water. You can buy aluminum "rollers" on which to roll up your cover when you want to use the pool but you should buy a pure white plastic sheet to put over the rolled up cover to prevent excessive heat during the day from damaging the cover. Sunlight duirng the hotter summer months will cause a very high temperature buildup in the center of the rolled up cover and may even cause some of it to melt. If you leave solar covers on the pool for long periods of time, you will raise the temperatur of your pool water quickly and probably too high so be sure to take it off after two or three days so water can cool again.