2016-0685
2017-10-02
materials.
pH:
a value that indicates how acidic or basic the spa water is.
Result if too low – Corroded metals, eye & skin irritation, and destruction of total alkalinity.
Result if too high – Scale formation, cloudy water, shorter filter/heater runs,
eye & skin irritation, poor chlorine efficiency.
Total Alkalinity (TA):
indicates the degree of the water’s resistance to pH
change. It determines the speed and ease of pH change, so always adjust
total alkalinity before adjusting the pH level.
Result if too low – Corroded metals, eye & skin irritation. Low alkalinity will
cause the pH to be unstable. Result if too high – Scale formation, cloudy
water, shorter filter/heater runs, eye & skin irritation, high chlorine demand.
Calcium Hardness (CaCO
3
):
refers to the amount of calcium and magnesium dissolved in
the water. Result if too low – Difficulty balancing water, corrosion of metal components, eye &
skin irritation and water foaming.
Result if too high – Scale formation, cloudy water, eye & skin irritation, difficulty balancing
water and filter/ heater inefficiency.
Saturation Index (SI):
temperature, calcium hardness concentration, total alkalinity and pH
represent the main factors influencing scale formation. The tendency of water to either form
scale or corrode is indicated by the Saturation Index (SI):
SI = pH+TF+CF+AF-12.1
*Where: TF = Temperature Factor; CF = Calcium Hardness Factor; AF = Total
Alkalinity Factor
Water Temperature
TF
Calcium
Hardness (ppm)
CF
Total
Alkalinity (ppm)
AF
(ºC)
(ºF)
8
46
0.2
75
1.5
50
1.7
12
54
0.3
100
1.6
75
1.9
16
61
0.4
150
1.8
100
2.0
19
66
0.5
200
1.9
150
2.2
24
75
0.6
250
2.0
200
2.3
29
84
0.7
300
2.1
300
2.5
34
93
0.8
400
2.2
400
2.6
40
104
0.9
500
2.3
--
--
--
--
--
1000
2.6
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--
Test the water pH, Temperature, Calcium Hardness and Total Alkalinity levels. Use the
equivalent Factors in the SI equation.
SI = 0, Balance