

New to pool ownership, first time opening. It's a very old concrete pool with an epoxy-based paint approx. 9 years old. When I opened the pool it was a deep green. I have been following the SLAM method for 10 days now with daily backwashing and brushing and can't improve the cloudy water. I decided to replace the filter sand on day 7, so it's been 60 hours of 24/7 filtering with new sand and constant brushing and no improvement. Frustrated with the cloudiness I decided to partially drain and refill the pool this morning. When I rub my hand on the pool wall a milky white substance comes off (feels a bit slimy). I talked to the former owner's pool guy on the phone and he says it sounds like calcium build-up and needs an acid wash. We're wondering if it's actually the paint due to its advanced age and/or improper water chemistry. I have a K2006 test kit. The readings today were:
FC - 13ppm (have been maintaining at 16ppm)
CC - 1.5ppm (has been under 0.5ppm for several days, but we had a storm last night lots of debris in water this morning)
TA - 90ppm
CH - 200ppm
pH was high before starting SLAM, but I added the poolmath suggested amount of muriatic acid
CYA - 40ppm (last tested about a week ago)
Pool Math says CH is low, am I experiencing chalking paint? Any help is appreciated!