Chlorine (bromine is similar and for brevity will not be further mentioned) has a list of properties that make it an ideal sanitizer for pools/ spas. Let's look at these properties.
Sanitizer: Free available chlorine (FAC) (hypochlorous acid) is a sanitizer. It enters through the bacterial cell wall and kills the organism by destroying the sulphur groups on the cell's enzymes, causing the cell's metabolism to stop, resulting in the cell's death.
Fast Kill Times: Not only does FAC kill bacteria - it does it very quickly. The Association of Analytical Chemists uses a kill time of 30 seconds at 0.6 ppm FAC to completely destroy a given concentration of bacteria as a standard for a swimming pool disinfectant.
Stable Residual: FAC is stable enough in solution to allow a residual to exist in every portion of pool water. Such FAC residuals "stand guard" against the presence of bacteria which will be quickly destroyed.
Oxidizing Agent: While not the most vaunted property of chlorine, its ability to oxidize is the key to its usefulness as a sanitizer. It has been estimated that over 90% of the FAC residual is used to oxidize organics introduced into the pool by bathers. if the purpose of FAC was only to kill bacteria, much lower levels of chlorine could be allowed. it is the oxidative properties of chlorine which make it the workhorse of cleansing pool/ spa water.
What Makes Chlorine Unique?
