Langelier Saturation Index for Hot Tubs

The best thing you can do for your hot tub is to keep the water properly balanced. Use the Langelier Saturation Index (LSI) to determine if your water chemistry is within a healthy range.

After testing your water, enter the measurements for your hot tub into the calculator.

• If the Langelier Saturation Index hot tub result is between -0.5 and 0.5, your water is balanced.

• If the result is below -0.5 or above 0.5, your water is undersaturated or oversaturated, which can cause corrosion or scale buildup.

Adjust your pH, Total Alkalinity, and Total Hardness levels as needed, then retest until your water is balanced.

Determine Your Water’s Saturation Index

Test the water for pH, Alkalinity, Total Hardness and Temperature.  Then, enter the information below.

Take a closer look at each component of hot tub water balance in detail. For quick reference, click here to download a printable copy of the Langelier Saturation Index table.