Hi! I have a VERY dirty/dusty yard. (no grass). I get a lot of silt into my pool, and weekly, I vacuum and sweep the pool.
I also just had my pool re-plastered white, 10 months ago. I maintain my water using the TF 100 kit religiously each week using the BBB method, keeping all measurements in the safe zone, except I keep the ph around 7.5-7.8 to get the chlorine to work better.
About 3 months into the new plaster, I started seeing a 2.5 foot thick ring forming 1/2 way into the pools deep end, all the way around the deep end. And also a splotchy/dirty looking floor of the shallow end. After 10 months now, Its a pretty dark ring, and dark splotchy floored shallow end. I called the plaster company. They came out and told me that the Cl can settle into a layer after the pump turns off, and its causing the pH to rise at that midway point in the pool, casing scaling at the walls but only at that part of the pool. This sounds like BS to me. They said 7.5pH-7.8pH is too high ad could be exacerbating the problem, and I should keep it around 7.0pH-7.2pH and sweep it like crazy for a few months to bring down the scaling that's trapping the silt when I sweep. They also suggested using a 50% metal 50% poly brush. Over a few months they said I should be back to normal. As a test...They used a fine grit sanding disc and rubbed it lightly on a small section of the bottom of the shallow end and it *seemed* to work to remove a small part of a dark area, all in a small puff of white plaster that came off along with it... but it was hard to tell.
Is this legit?! Or should I just do a non-drain acid wash for a few days? Thanks!!
BTW- No heater, water temp is between 68-80deg (winter to summer) in Los Angeles.