Water Hardener
Calcium Chloride is added to swimming pool water to make it 'harder' - it increases the level of hardness salts in the water.
Calcium Chloride - when added at to a pool the rate of 1.5kg per 100 cubic metres of water, should raise the Calcium Hardness level by 10ppm. The recommended level for hardness salts in swimming pool water is 75 to 150mg/litre. If your mains water has less than 40 mg/l of calcium hardness salts it is very aggressive - hungry for calcium, and is likely to attack exposed concrete and grouting.
Dose with calcium chloride by adding a measured quantity to a bucket containing warm water. Stir well as this is slow to dissolve, then pour off the liquid into the pool by the inlet, adding more warm water to the bucket and stirring until the solids have been dissolved and added to the pool.
Calcium chloride is not expensive to add to a pool, but in soft water areas it is advisable to check hardness levels weekly and add to keep it in the range 75 to 150ppm or mg/l, as the long term cost can be high. Water that is 'calcium hungry' will attack grouting and other exposed concrete surfaces, which can cause expensive damage over the years!
