Water Parameters
Managing the quality of Swimming Pool water, is essential if bather comfort and health and safety is to be maintained.
The following table details recommended water parameters for swimming pools
Free Chlorine | 1.0 to 2.0 ppm |
Combined Chlorine | No more than 1/3 of Free Chlorine |
pH | 7.2 to 7.6 |
Total Alkalinity | 80ppm to 150ppm |
Calcium Hardness | 200ppm Minimum |
Total Dissolved Solids | 2000ppm Maximum |
Sulphates | 360ppm Maximum |
Cyanuric Acid | 200ppm Maximum |
Amongst other things, pH is a product your choice of disinfectant. Each disinfectant has its own pH, some disinfectants are very acidic, whilst others are very alkaline.
Disinfectant | Chemical | pH |
Chlorine Granules | Sodium Dichloroisocyanurate | 6.0 - 7.0 |
Chlorine Tablets | Trichloroisocyanuric Acid | 2.0 - 3.0 |
Chlorine Gas | Chlorine | 0.0 - 2.0 |
Liquid Chlorine | Sodium Hypochlorite | 12.0 - 13.0 |
HTH/Shock | Calcium Hypochlorite | 10.0 - 12.0 |
Multi-Function Chlorine Granules | Chlorine | 3.0 - 3.5 |
Multi-Function Chlorine Tablets | Chlorine | 3.0 - 3.5 |
Chloriniser Plus | Chlorine | 3.0-3.5 |
Water Balance
When your swimming pool water is balanced this means that the water is neither scale forming or corrosive and is in ideal condition.
The Saturation Index or Langelier Formula is used as a method to determine whether pool water is balanced.
Saturation Index / Langelier Formula
Temp
°C |
TF |
Caciuml
Hardness ppm |
CF |
Total
Alkalinity ppm |
AF |
T.D.S.
ppm |
TDS |
32 |
0.0 |
5 |
0.3 |
5 |
0.7 |
0
to 1000 |
12.1 |
37 |
0.1 |
25 |
1.0 |
25 |
1.4 |
||
46 |
0.2 |
50 |
1.3 |
50 |
1.7 |
||
53 |
0.3 |
75 |
1.5 |
75 |
1.9 |
1001
to 2000 |
12.2 |
60 |
0.4 |
100 |
1.6 |
100 |
2.0 |
||
66 |
0.5 |
150 |
1.8 |
150 |
2.2 |
||
76 |
0.6 |
200 |
1.9 |
200 |
2.3 |
2000
plus |
12.3 |
84 |
0.7 |
300 |
2.1 |
300 |
2.5 |
||
94 |
0.8 |
400 |
2.2 |
400 |
2.6 |
||
105 |
0.9 |
800 |
2.5 |
800 |
2.9 |
||
128 |
1.0 |
1000 |
2.6 |
1000 |
3.0 |
Formula
Saturation Index = pH + TF + CF + AF + TDS
If you have a positive result then your pool water is likely to be scale forming;
Or, a negative result indicates that your pool water is likely to be corrosive
Current standards state that the ideal result should be in between 0.0 to +0.5