Brookforge swimming pool engineers

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

BROOKFORGE SWIMMING POOL TIPS 2009 - CHELTENHAM - 01242 573572