Chlorine Lock

[PoolDoc]

1. Run your chlorine level up to 15 ppm. From what you say, you know your CYA > 100 ppm, so 10 ppm is appropriate

2. Add a box of borax, to bring your pH up a bit.

3. Get a gallon of *distilled* (MUST be distilled) at Walmart. Once your chlorine is 10 ppm or higher, mix 1/4 cup pool water with 1/4 cup distilled, then test pH. No adjustment factor needed.

4. Mix 1/4 cup pool water with 3/4 cup distilled. Be as accurate as possible in proportions. Mix, and test CYA. Multiply your result x4.