I have been having difficulty with metal stains returning to the floor and sides of my concrete pool. The pool is about 45,000 gallons and is approximately 6 years old. I have never had this trouble before, so I am assuming that the fill water I had trucked in this year after I painted the pool is the source of the metal.
I completed the Vitamin C treatment...lowering Cl level and pH level while I did this...this removed the stains...for a while. The stains are slowly creeping back (I'm sure they are metal in origin because chlorine tab does nothing on them while a Vitamin C tablet removes them.). I have been adding Metal Free at an insane rate...3 bottles during the Vitamin C treatment and at least one bottle a week as maintenance/or when I add water. They continue to return, even when new water is not added.
Any thoughts. I have gotten the impression that Metal Free may not be the best sequesterant from other threads, but I have trouble believing that it is that ineffective.
My water is perfectly clear... I have been trying to keep the Cl level from raising too high since this is what caused the terrible staining at the beginning of the year. I really do not want to do another Vitamin C treatment and knock the water out of whack for who knows how long again. I'm also afraid to shock the pool for fear that the stains will become darker.
I have almost come to the realization that I will have to live with these stains until the end of the season...when I can do another Vitamin C treatment before pumping most of the water out for winterization. Of course, this is probably another bad idea.
Any help would be appreciated.