Total Hardness (TH) is a measure of the concentration of dissolved minerals, mainly calcium and magnesium, in pool water. These minerals can come from a variety of sources, such as the pool water source, chemicals added to the water, and debris introduced into the pool.
The ideal range for TH in a swimming pool is between 200 and 400 ppm. If the TH is too low, the water can be corrosive and can damage pool equipment and surfaces. If the TH is too high, the water can become cloudy and cause scaling on pool surfaces.
To adjust the TH level, pool owners can use chemicals such as calcium chloride to increase the TH level, or chelating agents to reduce it. It is important to test the TH level of the pool water monthly and make adjustments as necessary to maintain proper water balance and prevent damage to pool equipment and surfaces.