Raypak PS-4 PS-8 Preparing Pool/Spa Water, General Water Chemistry, Si = pH + Ti + Ci + Ai

1. Preparing Pool/Spa Water

General Water Chemistry

Salt is required only if you are using the chlorinator features on theAqua Logic Control. If you are NOT using the chlorinator, it is recommended that you follow all of the other chemistry recommendations be- sides salt. Refer to the description of the Aqua Logic configuration menu for information on enabling/ disabling the chlorinator (see pg 19).

Water Chemistry

The table below summarizes the levels that are recommended by the National Spa and Pool Institute (NSPI). The only special requirements for theAqua Logic are the salt level and stabilizer.

Saturation index

The saturation index (Si) relates to the calcium and alkalinity in the water and is an indicator of the pool water “balance”. Your water is properly balanced if the Si is 0 ±0.2. If the Si is below -0.2, the water is corrosive and plaster pool walls will be dissolved into the water. If the Si is above +0.2, scaling and staining will occur. Use the chart below to determine the saturation index.

Si = pH + Ti + Ci + Ai - 12.1

ºC ºF

1253

1660

1966

2476

2984

3494

39103

Ti

.3

.4

.5

.6

.7

.8

.9

Calcuim

Hardness

75

100

125

150

200

250

300

400

600

800

Ci

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.4

2.5

Total

Alkalinity

75

100

125

150

200

250

300

400

600

800

Ai

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.8

2.9

How to use: Measure pool pH, temperature, calcium hardness, and total alkalinity. Use the chart above to determine Ti, Ci,and Ai from your measurements. Insert values of pH, Ti, Ci and Ai into the above equation. If Si equals .2 or more, scaling and staining may occur. If Si equals -.2 or less corrosion or irritation may occur.

-.2 0 .2

CORROSIVE SCALING

OK

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