This results in conversion of bicarbonate to carbonic acid and carbon dioxide. For example, at start–up, the addition of 50 ppm cyanuric acid to a pool at 80ºF, pH 7.4, 100 ppm alkalinity, and 1000 ppm TDS will lower the pH to 7.0.

Does adding cyanuric acid affect pH?

If your pH goes down, the effectiveness of your chlorine goes up. This is commonly understood. But in the presence of cyanuric acid, the relationship between pH and chlorine is substantially altered. For example, if your pool maintains a pH of 7.2, about 63 percent of the chlorine is in its active form.

Does adding CYA lower pH?

CYA is acidic and it keeps on lowering PH the entire time it is dissolving. Metal Free is also somewhat acidic.