Hi, I accidentally dropped a full bottle of muriatic acid into the pool. No idea how much went in, about a quarter of it is missing, but maybe water got back into the bottle. My question is what color would the PH test be for really low numbers. My test only goes down to 6.8 and the color of the water is like a rust color that I don't recognize. In other words, how can I guesstimate how low the PH got, and also, how low a PH would do damage to the equipment? Thank you.