347
PO
S AVE THESE INSTRUCTIONS
(347PO) SPA ENGLISH 7.5” X 10.3” PANTONE 295U 05/21/2020
English
Page 16
SPA WATER CHEMISTRY AND BALANCE
Preferred Water Chemistry Reading
Minimum
Ideal
Maximum
Free Chlorine
2 ppm
2 - 4 ppm
5 ppm
pH
7.2
7.2 - 7.6
7.8
Total Alkalinity (TA)
60 ppm
80 ppm
120 ppm
Calcium Hardness (CaCO
3
)
100 ppm
150–250 ppm
350 ppm
Saturation Index (SI)
–0.3
0
+0.3
Water Temperature
20ºC / 68ºF
20–40ºC / 68–104ºF
40ºC / 104ºF
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
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
--
--
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.
