A high pH level can come from the chemicals used in the pool or a lack of proper maintenance. Cloudy water is a sign of high pH and the heightened pH also affects swimmers in the pool. A high pH level means the pool is too alkaline. When you find the pH level to be high, adjust it immediately, before others use the pool.
High Total Alkalinity
If the total alkalinity of the swimming pool is high, then it is almost a certainty that the pH level is high as well. The total alkalinity, or TA, is a measurement of the alkaline substances, including carbonates and bicarbonates, in the pool water. If the TA is high, the pH level will be difficult to adjust and the process of lowering the TA involves adding either dry or liquid acid to the pool water. It could be a process that takes days or even weeks, depending on just how high the TA level has climbed.
When the pH level is low, you add chemicals such as sodium carbonate to the pool water to raise the pH. It is vital to add the correct amount of this chemical, depending on how much you want to raise the pH, and just how much the volume of water in the pool is. If you simply dump the sodium carbonate into the water based on a low pH test, or you overestimate the amount needed, it will probably mean a high pH level.
Shocking the Pool
Shocking a pool with calcium hypochlorite is effective and popular because it provides a quick chlorine boost and is completely soluble. Calcium hypochlorite, which has a pH of 11.8, is also alkaline, which in turn causes the pool's pH level to rise. Lithium hypochlorite, which has a pH of 10.8 will also raise the pool's pH. When either of these is used regularly to shock the pool water, the water needs to be diligently tested, and the pH level adjusted regularly, to prevent the pH from rising over time.
Dangers and Correction
The high pH level endangers swimmers with burning eyes and noses, as well as itchy, dry skin. In addition to the pool's cloudy water, the chlorine used as a disinfectant will not work as efficiently, causing you to use more chlorine just to get the right amount of effectiveness. Scale that forms from the calcium and carbonates in the water hinder water circulation. Lower the high pH by adding either muriatic acid or sodium bisulphate to the water.