Swimming pool disinfection

In swimming pool maintenance, both hydrochloric acid (HCl) and sodium hypochlorite (NaClO) play distinct yet complementary roles in ensuring water hygiene and safety.

Hydrochloric acid is primarily used for pH adjustment. pool water tends to become alkaline due to factors like chlorine usage and environmental contaminants, which reduces the effectiveness of disinfectants. By carefully adding hydrochloric acid, the pH level can be lowered to the optimal range of 7.2–7.6, enhancing the activity of chlorine-based disinfectants and preventing skin irritation or eye discomfort for swimmers.‌1 Additionally, hydrochloric acid aids in cleaning pool surfaces by dissolving mineral deposits and scale buildup, maintaining the aesthetic and functional integrity of the pool infrastructure.

Sodium hypochlorite, a widely employed chlorine-based disinfectant, serves as the primary agent for microbial control. It effectively kills bacteria, viruses, and algae by disrupting their cellular structures, thereby preventing waterborne diseases and maintaining clear, safe pool conditions.‌3 Its oxidizing properties also help break down organic contaminants such as sweat and sunscreen residues, ensuring water clarity and reducing unpleasant odors.‌4 Regular application of sodium hypochlorite in recommended concentrations guarantees continuous disinfection, though it requires careful monitoring to avoid overuse, which can lead to chloramine formation and irritations.‌5

Together, these chemicals create a balanced water treatment system: hydrochloric acid optimizes the chemical environment for efficient disinfection, while sodium hypochlorite actively purifies the water, collectively safeguarding swimmer health and pool longevity.