SPA WATER ChEMISTRY AND BALANCE (continued)
Particular care should be taken with chemical treatment of the water with special attention to disinfectant
limits and control of pH values. The use of ozone or UV, where applicable, shall always be accompanied by
residual disinfection with an oxidising biocide (e.g. Chlorine or Bromine or other biocide products, compatible
with manufacturer's recommendations).
Improper use of chemicals may result in degradation, damage and other imperfections of the spa surface
and other spa components (typically discolouration of materials, corrosion of metal parts).
Free chlorine: is the chlorine residual present in the spa water.
Result if too low – Inadequate level of disinfection.
Result if too high – cause odor problem, skin & eye irritation, corroded metals and other 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
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):
*Where: TF = Temperature Factor; CF = Calcium Hardness Factor; AF = Total Alkalinity Factor
Water Temperature
(ºC)
8
12
16
19
24
29
34
40
Test the water pH, Temperature, Calcium Hardness and Total Alkalinity levels. Use the equivalent Factors
in the SI equation.
SI = 0, Balance
If SI > 0, Scaling or cloudy water condition.
If SI < 0, Corrosive to metals or eye & skin irritating condition.
The SI is considered satisfactory if the value is within -0.3 to +0.3 range. Zero being perfect.
S AVE THESE INSTRUCTIONS
(344IO) SPA (JET + BUBBLE) ENGLISH 7.5" X 10.3" PANTONE 295U 08/09/2019
): refers to the amount of calcium and magnesium dissolved in the water.
3
SI = pH+TF+CF+AF-12.1
Calcium
TF
Hardness (ppm)
(ºF)
46
0.2
75
54
0.3
100
61
0.4
150
66
0.5
200
75
0.6
250
84
0.7
300
93
0.8
400
104
0.9
500
English
Total
CF
Alkalinity (ppm)
1.5
50
1.6
75
1.8
100
1.9
150
2.0
200
2.1
300
2.2
400
2.3
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344
A
AF
1.7
1.9
2.0
2.2
2.3
2.5
2.6
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