I think most of us agree that the main advantage of a solar blanket is to reduce evaporation at night and its corresponding heat loss. I can certainly testify that there is little heat gain during the day, at least at my location. My question is, why can't we just float a heavy piece of plastic sheeting on the water? Or would it just sink? Spending money on all the cute little diamond shaped bubbles that break down in the UV rays seems foolish if there is an alternative way to stop evaporation.

Set me straight all you experienced experimenters!