Langelier Saturation Index

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Want to know the best thing you can do for your swim spa?

Make sure it’s balanced and within ideal parameters. Test your water and adjust as needed to meet the ideal levels for your swim spa water:

Free Chlorine: 1.0 – 3.0

Total Alkalinity: 80 – 120 ppm

pH: 7.2 – 7.8

Total Hardness (also known as Calcium Hardness): 200 – 400 ppm

Determine Your Water’s Saturation Index

Fill in the four boxes below to determine your water’s saturation index:

If the result is between -0.5 and 0.5 the water is balanced.

If it is below -0.5 or over 0.5 your water is either over- or under-saturated, which can lead to problems.

Add the necessary adjustment products to bring your pHTotal Alkalinity and Total Hardness within the proper standards, then retest.

In the next sections, we will discuss each individual component of water balance in detail. Click here for a printable copy of the Langelier Saturation Index table.