Last fall we had a local pool store install a safety cover and also close the pool for the winter. This spring, we have stains on our stamped concrete that look like chemicals were splashed when they closed the pool. These stains were definitely NOT there before the pool was closed for the winter. I talked to the pool store about it and they clearly have no intention of taking responsibility. I’d still like to try to fix the stain spots because our pool/concrete is only 3 years old and it’s very noticeable to me. Any suggestions on how to try to fix these stain spots? I tried gently power washing and also scrubbed the spots with Dawn, but it did nothing. Photos attached - these are only examples...there are spots all around the perimeter of the pool and there’s even an area where there’s a blue haze around the stains but I can’t get that photo to upload. Thanks.