I am a relatively new owner of a 40 year old pool. I have been following the BBB method, but am having trouble preventing the pool from staining. There have been a number of new stains that have developed in the last 4 months since I bought the house (most look like dirt). I have kept my FC at shock level for the last 2 weeks, but there has been no reduction. And I got a new purple stain in the last 2 days (the only new thing I did was add borax to raise pH). My calcium level is low, and I am traveling for the next few days so I was trying to get the pH up to control my CSI.
See attached pics. Here are my latest test results.
Inground Gunite pool