How many times have you been around a swimming pool and experienced a strong chlorine smell? The odor is deceiving, and most people believe it is due to too much chlorine in the water. It does defy logic in our minds, as the odor smells exactly like chlorine.
The truth of the matter is this strong chlorine smell comes from chloramines. These are chemical compounds that build up in pool water and can become irritants to our eyes, lungs, and skin. Chloramines are derived from the combination of chlorine in the water (which is the sanitizer), and other chemicals which the chlorine is acting on. These are substances such as perspiration, body oils, suntan lotion, urine and other debris that may fall into the pool.
We add chlorine to the pool water to destroy germs and organisms that cause diarrhea, athlete’s foot, earaches, and other ailments should the water have no sanitizer in it. This is why many public pools have signs asking bathers to shower prior to entering the pool, which will wash many of these contaminants from the body.
Germs and harmful bacteria in the water are eliminated when the proper chlorine level is maintained in pool water. The amount of Free Available Chlorine is measured regularly to make sure there is enough to continue disinfecting until the next time the water is tested. The balancing act is to determine how heavy the bathing load will be until the next visit, and add enough chlorine to last that long while not raising the level too high to be harmful to swimmers. This is because as the chlorine disinfects, the residual amount left in the pool is gradually depleted. As the chlorine does it’s work, it reacts with perspiration, urine, and oils to form chloramines.
When one of the chemicals in chlorine, hypochlorous acid, reacts with ammonia, it forms chloramines. Ammonia is found in perspiration and urine. This can cause eye irritation and some swimmers immediately think the chlorine level is too high. In actuality, the chlorine level is too low. There is little to no odor in well-balanced pool water. Shocking the pool, also called superchlorination, is done to destroy the organic material and ammonia which combine with chlorine to produce chloramines. So the next time you experience a strong chlorine smell, you will know where it comes from.