The presence of hard water or an overabundance of alkalinity-boosting chemicals often leads to high alkalinity in swimming pools. Pool owners should aim for a total alkalinity of 80 to 120 parts per million in concrete pools and 125 to 170 parts per million in vinyl, fiberglass or painted pools.
The total alkalinity of a pool is one of three factors in balancing the water of a swimming pool. Water hardness and pH levels are also important, and one factor often influences another.
To combat the chemical imbalance caused by frequent acidic rain, some pool owners regularly add alkalinity boosters to a swimming pool to negate the nitric or sulfuric acid introduced into the water. This can lead to an overestimation of how much of the booster is needed and, thus, an increase in alkalinity levels.
Excessive calcium and magnesium deposits increase the alkalinity in a swimming pool. If this is the case, the water in the pool appears cloudy, and, in extreme cases, deposits of white scale crust form on pool equipment and surfaces.
Body sweat and lotions also have the tendency to raise alkalinity levels.
To lower a pool's total alkalinity, one must introduce a pool-safe acidic compound, such as sodium bisulfate or muratic acid, to the water.