IG pool and spa/ 28.5K/ 12 year old, with 4 month new plaster/ Purex FNS60 DE filter/ 2HP centurion/ polaris 360
Houston TX suburb
I had a replaster job in February. Within a couple of weeks, brown stains along the edging of the toe tiles was evident. The installer applied acid directly to the areas with a pole and hose. It helped a little initially but the stains got progressively worse. I drained the pool low enough for the installer who had the tiles cut out and installed new tiles using the plaster to install them as opposed to the thin set. He blamed the problem on thin set. Now less than 2 weeks later there is still brown stains in some of the areas where they cut out because the initial stains were wider than what they cut out. In addition, the pool has developed brown spots on the steps and along the walls. It seems to remain about the same and not getting worse but will not go away.
I have tested for metals. There is no Iron or copper and the Vitamin C trick does not change the spots. I have used a chlorine tablet to scrub and it does not change anything. The spots are a light brown.