Last night I went to bed with a very clean pool. My Polaris was cleaning the bottom but there was nothing left to clean, completely spotless bottom! Today I woke up and saw the surface of my pool to have a lot of white cloudy material on it, I was puzzled so I went outside to look at it. In the bottom were a bunch of rocks! They all appear to be white rocks, they are all different sizes from pebbles to fist-sized chunks and everything in between and all in the shallow end of the pool. It did rain last night but it doesn't look like anything was around the pool and the two gates in my fence were still closed. What caused this??? Has this happened to anyone else before???