Calculating The Saturation Index; Tds Factor; Langelier Saturation Index Factors - Pentair INTELLICHLOR IC15 Installation And User Manual

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Calculating the Saturation Index

The saturation index is a formula that relates pH, calcium and alkalinity in the pool water. A well balanced
pool water will have a formula result range between -0.3 and 0.3 Outside this range, the pool water is out of
balance, potentially damaging pool equipment or scaling the SCG.
SI = pH + CHF + AF + TF + TDSF
Saturation
Index
Cyanuric acid in the form of cyanurate ions contribute to alkalinity. Thus, a correction must be made to total
alkalinity. We subtract 1/3 of the cyanuric acid level from the reading obtained in the total alkalinity test.
Total Alkalinity - 1/3 Cyanuric Acid = Corrected Alkalinity
This correction can be considerable in established pools with high cyanuric acid levels; for example, at 240
ppm cyanuric acid, the correction amounts to 80 ppm (240 ÷ 3 = 80).

TDS Factor

(Factors shown below are based on the actual measured value for the particular parameter)
TDS Factor
<1000 12.10
1000 12.19
2000 12.29
3000 12.35
4000 12.41
5000 12.44

Langelier Saturation Index Factors

Note: Use the reading closest to your actual reading in choosing the factor.
Total alkalinity in this context refer to the total of carbonate and bicarbonate alkalinity. If cyanuric
acid is used, a correction factor must be used (see cyanuric acid Table 2 on page 14).
IntelliChlor Salt Chlorine Generator Installation and User's Guide
pH as Calcium
Hardness
tested
Factor
The equation to calculate Si is:
Alkalinity Tempera-
ture
Factor
Factor
TDS
Factor