Gas chlorine has what effect on the pH of water?

Gas chlorine has a lowering effect on the pH of water when it is dissolved. This is primarily because gas chlorine (Cl2) reacts with water to form hydrochloric acid (HCl) and hypochlorous acid (HClO), both of which contribute to an increase in the concentration of hydrogen ions (H+) in the water. This increase in hydrogen ions results in a decrease in pH, making the water more acidic.

In pool management, maintaining proper pH is essential for effective disinfection and overall water quality. If gas chlorine is used without adjusting the pH afterward, it can lead to overly acidic conditions, which can cause corrosion of pool equipment and irritation to swimmers' eyes and skin. Thus, understanding the effect of gas chlorine on pH is crucial for maintaining suitable water chemistry in commercial pools.