Pool Water pH

To make the most of your swimming pool and avoid higher pool maintenance costs, pay close attention to pool water pH. The minimum pH in pool water is 7.2 and the maximum is 7.8, with the ideal range of pH in pool water between 7.4-7.6. If pool water pH is too low or too high, it will cause problems for swimmers and for the pool.

Pool water pH is important because it affects the balance of all the other pool chemicals, such as chlorine, in pool water. pH, a measure of hydrogen ion concentration in water, indicates the relative acidity or basicity. pH is measured on a scale of 0 (high acidity) to 14 (high basicity); a pH of 7 is neutral. A pH of 7.4 to 7.6 is ideal for pools because it is the most comfortable to the human eye and allows chlorine to do its job of sanitizing, while keeping pool water from being corrosive or conducive to scale formation.

If pool water pH is too low or too high, problems arise that can cause discomfort to swimmers, such as burning eyes. Pool maintenance can also become more stressful and expensive due to issues like algae growth or corroded pool parts.

When pool water pH is low, it means that pool water is too acidic. Low pH can cause swimmers' noses and eyes to burn and swimwear to fade and deteriorate; these problems are often mistakenly attributed to too much chlorine. But when pH is low, chlorine is actually used up too quickly, which means that the pool won't be properly sanitized.

Low pool water pH dissolves the surface of plaster pools and the grout of tiled pools, creating a haven for algae. Metals such as pool equipment and plumbing connections corrode when pool water pH is low, which also causes sulfates to form which can cause brown and black stains on the floor and walls of the pool. Pool stains can be costly and difficult to remove and make the pool look less attractive.

When pool water pH is high, it means that pool water is too alkaline. Like low pool water pH, high pool water pH makes swimmers' noses and eyes burn. It also dries out the skin, making it itchy and uncomfortable.

When pool water pH is high, calcium combines with carbonates to form scale. The waterline of the pool often turns black where dust and dirt have been trapped by scale. Scale also interferes with sand pool filters by making them less efficient. Because of these factors, pool water will turn cloudy, making the pool less attractive.

High pool water pH also makes chlorine less efficient. Most chlorine added to the pool will go to waste without having accomplished the job of sanitizing pool water. This means that the pool owner will spend more money on chlorine than they should. When chlorine doesn't seem to be sanitizing the pool properly, pool water pH should always be tested.

Because it has an effect not only on swimmer comfort but on the longevity of the pool, it is very important to test pool water pH often using a test kit.