Have you ever wondered about that irritating smell and taste which we encounter while swimming? It is due to Trichlorocyanuric Acid - a water treatment chemical known popularly as TCCA.
TCCA is used in swimming pools to furnish chlorine and hence acts as a disinfectant. When added in the pool, it combines with water to give Cyanuric Acid and Hypochlorous Acid (HClO).
This released HClO is capable of giving free chlorine to swimming pools. Furthermore, Cyanuric Acid acts as a stabilizer and protects the free chlorine from sunlight. Chemically, Cyanuric Acid stops the conversion of HClO into hypochlorite ion (ClO-) which has low microbial activity.
Free chlorine upon reaction with ammonia and other waste substances from urine, perspiration etc. gets converted to combined chlorine which should be eradicated from pool in a timely manner. Pools are fed with chlorine shocks once or twice every month to clean the pool. These shocks contain concentrated chlorine which reduces the growth of algae residue and bacteria in the water bodies.
As far as quantity is concerned, Chlorine should be present in 1-4 ppm for the pool to become an ideal one. One more important characteristic is the pH of the pool water, which should be maintained between 7.2-7.6. This pH range is basically same as the pH of human tears and hence maintaining it will prevent our eyes from burning. Less than 7.2 would render the pool acidic and lead to the corrosion of pipes and may attack pool walls. On the other hand, higher pH will make the water alkaline and reduce the effectiveness of chlorine. Some common chemicals are used to adjust the pH. Lower pH is achieved using Hydrochloric Acid while higher pH is obtained by adding sodium carbonate or bicarbonate.
TCCA-90 is the most common product available and contains 90% Chlorine. It is available in various forms and varied sizes such as granular, tablet etc.