If a pool has a saturation index reading of +0.2, how is the water classified?

A saturation index reading of +0.2 indicates that the water is classified as balanced. This value suggests that the water has a slight tendency toward being scale-forming but is primarily in a state of equilibrium where the water neither has the capacity to corrode surfaces nor deposit calcium carbonate scales excessively.

In pool chemistry, the saturation index is used to assess the potential of water to either corrode pool surfaces or to form scale. A reading of 0 would indicate that the water is perfectly balanced, while a positive value shows a slight potential for scale formation without significant corrosive activity.

In contrast, a negative saturation index would suggest corrosive tendencies, where the water can potentially damage pool surfaces and equipment, making the water classified as corrosive. Therefore, a reading of +0.2 indicates that while there is a mild tendency toward scale formation, it does not reach a level that is problematic, hence the classification of balanced water.