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Preparing pool/spa water, General water chemistry, Si = ph + ti + ci + ai - 12.1 – Raypak PS-4 PS-8 User Manual

Page 6: Water chemistry

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ºC ºF Ti

Calcuim

Hardness

Ci

Total

Alkalinity

Ai

53

60

66

76

84

94

103

12

16

19

24

29

34

39

.3

.4

.5

.6

.7

.8

.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.

Si = pH + Ti + Ci + Ai - 12.1

-.2

0

.2

CORROSIVE

SCALING

75

75

100

100

125

125

150

150

200

200

250

250

300

300

400

400

600

600

800

800

1.5

1.9

1.6

2.0

1.7

2.1

1.8

2.2

1.9

2.3

2.0

2.4

2.1

2.5

2.2

2.6

2.4

2.8

2.5

2.9

OK

1. Preparing Pool/Spa Water

General Water Chemistry

Salt is required only if you are using the chlorinator features on the Aqua 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 the Aqua 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.

3