Free Chlorine
Whether tablet, liquid, or powder form, the chlorine in a pool kills an array of viruses, bacteria, and organic matter such as sweat, urine, and fecal matter. Chlorine disinfects the water to remove most pathogens that can harm swimmers.
Free chlorine levels refer to the chlorine in pool water that is “fresh”—it has yet to react with any contaminants. Too much or too little of this chemical in the water can be potentially harmful to swimmers and your pool equipment.
Without enough free chlorine to attack invading contaminants, pool water becomes susceptible to a variety of undesirable effects.
Algae may grow, turning the water murky with slimy green patches along the pool’s floor and walls. The unwanted green visitor can also coat the cartridges in some kinds of pool filters—necessitating more frequent cleaning that shortens product lifespan.
Without sufficient chlorine, the water’s appearance may also become cloudy from organic matter that the wind blows in and swimmers bring in, such as sweat, make up, body oils, and suntan oil.
Worse yet, too little chlorine gives safe harbor to water-borne diseases! When swimmers (including pets) introduce biological matter—from urine to bacteria infecting an open sore—there is not enough sanitizer to defeat the pathogens. As a result, opportunities increase for transmission of infectious microbes and the illnesses they cause.
On the flip side, high levels of free chlorine cause its share of issues. Too much can sting swimmers’ eyes and irritate their skin. Elevated levels of this chemical can cause harsh, bleach-like fumes that are downright nasty to inhale and irritating to swimmers’ lungs.
Pools need enough free chlorine to kill unwanted pathogens and contaminants, but not so much that is poses noxious effects to pool users. It’s all about achieving balance with a range of 1.5 to 2.5 ppm. Note: Pools with ozone systems and/or ultraviolet sanitizers require dramatically less chlorine—only .5 to 1 ppm.