This Langelier Saturation Index (LSI) Calculator will compute the Calcium Saturation Index. It indicates the amount of calcium that can be held in swimming pool water. Water that is oversaturated may result in calcium being deposited onto the pool plaster and tile. Water that is undersaturated may result in calcium being leached from the pool plaster, causing eching.
The recommended range for the Saturation Index in pools and spas is -0.3 to +0.5.