Pentair IC60 - Calculating the Saturation Index; Saturation Index Factors

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IntelliChlor Electronic Chlorine Generator Installation and User’s Guide
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 IECG.
The equation to calculate Si is:
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).
Saturation Index Factors
SI = pH + CHF + AF + TF + TDSF
Satu r ation
Index
pH as
tested
Calciu m
Ha r dness
Facto r
Alkalinity
Facto r
Te m pe r a-
tu r e
Facto r
TDS
Facto r