Calcium hypochlorite (Ca[OCl]₂) and liquid chlorine are also commonly used chlorine sanitizers. Ultimately, these products do the same thing as trichlor: they kill bacteria and prevent disease. However, the process of applying and maintaining these chemicals is different. Calcium hypochlorite and liquid chlorine both disperse immediately when added to the pool water, rather than slowly dissolving over time. This puts a large amount of chlorine into the pool at once, which is sufficient until the next dose.
For example, if a user adds calcium hypochlorite to the pool and 10 kids go swimming the next day, there is a good chance all the chlorine would be gone when they are done. If trichlor was being fed into the pool, the chlorine residual would be supplemented throughout the day and probably still be measurable after the pool party. In the case of calcium hypochlorite and liquid chlorine, it would need to be added again within a day or two to maintain the residual. This is clearly more work for the pool owner. If a service company were taking care of the pool, it would not receive more chlorine until the technician returned to add it, leaving the pool at risk.
In addition, trichlor already has cyanuric acid (CYA) blended into it. CYA is sunscreen for the sanitizer. Without it, the ultraviolet (UV) rays of the sun burn up chlorine very quickly. With CYA, it lasts 13 times longer in the sunlight. Using trichlor as the sanitizer of choice allows users to add product less often, feed continuously, and lose less chlorine to waste—making it an extremely efficient form of chlorine. Calcium hypochlorite and liquid chlorine do not contain CYA; however, it can be added separately, but that adds an extra step required to protect the chlorine residual.
Sanitizer choice also impacts water balance. While trichlor has a low pH, both calcium hypochlorite and liquid chlorine have high pH. The slow feed of trichlor minimizes the impact of a low pH in a pool, but the “all at once” addition of calcium hypochlorite or liquid chlorine often cause the pH to rise dramatically, leading to cloudy water and scale issues. Further, frequent use of calcium hypochlorite adds calcium to the pool overtime, and eventually, calcium levels will get too high, leading to problems with scaling, and surface damage. As a result, a scale inhibitor product will be needed to keep the water clear.
Ultimately, there are many choices to pool care. Some categories, such as sanitizers, are non-negotiable and an integral part of every pool care program. Other categories, such as ancillary products, are not necessary, but can lead to an easier and more efficient pool maintenance routine. Establishing key products and determining what works best for each pool is the key to successful water quality management. The result is clear, safe, hygienic water and happy swimmers.
Author
Alicia Stephens is the director of training and education for Biolab Inc. In her 22 years with the company, she has focused primarily on education, training, and development, as well as technical support and new product research and integration. Currently, Stephens supports all branding, education, and training initiatives for the Biolab Pro Dealer division. She can be reached via email at alicia.stephens@biolabinc.com.
