I had my pool replastered (white) last August (10 months ago). Since opening the pool this spring, there are many areas of grey stains appearing on the floor. Some of the stains actually look like dirt resting on the floor, shaped in a swirl moving towards the main drain. Nothing at all on the walls. Brushing the pool with nylon brush certainly does not have any impact on the stains. If I feel the surface where the stains are, it feels rough on the surface, similar to sandpaper. Is this a sign of calcium scaling? Is this something that could have been caused by improper workmanship during the plastering?
If there is a way to remove the stains without draining the pool and doing an acid wash, that would certainly be my preference. I am about to try using direct application of muriatic acid to a couple of spots combined with elbow grease and a stiff wire brush, to see if this has any impact on the stains. However, I wanted to do my homework first to make sure I am taking the best approach.
Here are my recent water test results:
I will post some pictures shortly.
I would appreciate your feedback and suggestions on how to move forward.