The Effects of Adding Chlorine to a Cloudy Swimming Pool

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When you picture a perfect swimming pool, your probably see crisp, clean water sparkling in dazzling sunlight. But when your pool water is murky or cloudy, that swimming oasis loses its appeal. Cloudy pool water can be caused by a variety of factors, from contamination to equipment issues. Although adding chlorine can help clear the water, it might only be a temporary solution.

How it Works

Once chlorine is added to water, the chlorine molecules combine with the water molecules and produce hypochlorous acid and hydrochloric acid. The temperature and acidity of the water determines how much of each acid is produced. The hypochlorous acid moves through the water, breaking open microorganism cell walls and destroying the cell’s inner structures. As a result, the cell becomes deactivated and no longer affects the pool water. This process continues until the hypochlorous acid also becomes deactivated.

Cloudy Water Causes

Because chlorine is responsible for killing all the microorganisms that invade your pool, low chlorine levels could certainly be the cause of your cloudy water. In fact, the Pool Solutions website claims that “inconsistent swimming pool chlorination” is the most common cause of cloudy water. Although adding chlorine can help with the water’s appearance, it will only be a temporary solution if the cloudy water is caused by an unrelated problem. Cloudy water could be caused by algae growth, poor water circulation, improper filter size, dirt, debris, insufficient sunlight and high water temperatures, among other factors. The Pool Solutions website offers a list of 100 possible causes for cloudy water.

Chlorine Recommendations

Before adding chlorine to your swimming pool, carefully read and follow the manufacturer’s instructions, which should be printed directly on the chlorine packaging. Test your pool water regularly to ensure the water remains balanced. Free available chlorine levels should remain at 2.0 to 2.4 ppm, while combined available chlorine level should remain below 0.2 ppm. Ideally, your pool water’s pH should be 7.4 to 7.6, although a range of 7.2 to 7.8 is generally acceptable. If your pool becomes too clogged with contaminants, bacteria and algae, a shock treatment of high amounts of chlorination might be necessary.


Although chlorine is extremely beneficial for your pool water, it is still considered a hazardous chemical and must be handled carefully. Never mix chemicals or different types of chlorine together because that could cause a dangerous explosion or combustion. Avoid inhaling chlorine fumes or vapors. If you spill chlorine on yourself, rinse the area thoroughly with water. If chlorine gets into your eyes, irrigate with water and contact a physician. Ideally, wear gloves, durable footwear and goggles while handling pool chemicals. Store chlorine and all chemicals in a cool, dry place away from sunlight, pets and children.