Had an acid wash done professionally this past Thursday, having let the Ph fluctuate and rise too high over the past couple years. After they finished I see these two perfect circles in the deep end. I imagine the pump or some other piece of equipment they used to pull out the muriatic acid/water had circular feet on it. The company responded with "I'm not to sure what those are? No idea. Our method and cleaning has never or wouldn't make 2 perfect circles in your pool. Very strange." Any one ever see or hear of something like this before?