I had my liner replaced end of June and obviously had all new water trucked in. About 3 weeks later I noticed my steps and swim out were turning brown. Using a magic eraser I was able to clean them with the exception of right at the water line. I added a small amount of ascorbic acid to the eraser and the brown came right off. I assumed iron and must have gotten some real bad water. I have cleaned everything 3 times since for the same reason and the brown seems to be coming back quicker each time. I took a water sample to the pool store to check for metals and none were found. I am totally lost, no idea what could be causing this. In the 16 years I have had the pool I never had this problem. I should note the water is crystal clear. Below are some numbers, I test my own water with a TF-100 and only use bleach, borax and acid to adjust. As a side note I also noticed as soon as I started up the equipment after the liner replacement the pressure was way higher than it ever was before. Typically it runs about 10-12 and it was around 17. I have backwashed a couple of times and the pressure still does not come down to where it used to be, coincidence???
FC-7
CC-0
PH-7.6
TA-75
CYA-50
FC-7
CC-0
PH-7.6
TA-75
CYA-50
