Just had our pool replastered with plaster w/quartz. When they were getting ready to plaster, I saw some spots that looked like water seeping up through the coating they put on before plastering. I mentioned it to the plasterer, and he told me it was ok. After about 2-3 weeks spots started showing on the steps and built in benches. The spots are where the seeping was noticed. The plaster company said that they were caused from chemical imbalance. The alkalinity was low and the ph was high. We got the chemicals right within 2 weeks. Could the chemicals being off for that short of a time cause staining? They look like water spots on cement. I have uploaded picture. I have more if necessary.