Swimming Pool Water Quality
Within the Borough

In order to maintain acceptable quality the following parameters should be maintained:

• pH 7.2 - 7.6
• Free Chlorine 1.0 - 2.0 mg/l
• Combined Chlorine residual should be kept as low as 0.5 mg/l and should be no more than one-third of total chlorine.
• Total Alkalinity 80 - 150 mg/l
• Calcium Hardness 200 mg/l minimum
• Total Dissolved Solids (TDS) maximum 1000 mg/l above supply water TDS to an absolute maximum of 3000 mg/l (2000 mg/l preferable)
• Sulphate 360 mg/l maximum

Water balance is affected by:

• Temperature
• pH
• Total Alkalinity
• Calcium Hardness
• Total Dissolved Solids

The Langelier formula, sometimes called the Saturation Index, is used to determine pool water balance.  The Saturation Index (SI) = pH + Temperature Factor (TF) + Calcium Hardness Factor (CF) + Total Alkalinity Factor (AF) minus Total Dissolved Solids Factor (TDSF).

The value obtained should fall between 0 and 0.5 and indicates the water is in balance.

For further information contact Alan Sargent on 01483 444372.