Just had our pool redone. What could these stains be?
We have just had our 40+ year old Sylvan pool re-plastered. (we've only owned the property for 5 years) We also replaced the tile and the coping. One of the reasons we bit the bullet and had this done was because the inside of the pool was terribly rough and pitted. Also, there was quite a bit of staining, particularly on the steps.
Our problem is that the staining came back, right away, in the exact same places that it had been. They look like they could be organic but they most definitely are not. We brushed the pool down twice a day for 2 weeks and the chemistry is perfect. These stains don't budge. The company that did the works says that this is impossible as there is 3/4" ansylbrite on it. They also claim that it was acid washed and bond coated but I was watching the whole process and never saw that done. Can anyone guess what might be the problem?