Water hardness is a measurement of the amount of calcium and magnesium in your pool or spa. Generally about 70-75% of the total hardness of your pool or spa is calcium. Too much calcium in your pool or spa is undesirable.
It can cause the formation of calcium scale on the plaster or acrylic finish, or in the coils of a heater and can block the filter.
The amount of water hardness tends to increase in a pool or spa due to evaporation or the addition of refill water. The use of calcium hypochlorite also increases the water hardness. Generally when the water hardness reaches a level of 400 PPM, Approximately 25% of the pool or spa should be drained and refilled with fresh water. (1 grain/gallon equals 17.1 PPM).
Completely soft water without hardness is undesirable in a pool because the water tends to be corrosive. A minimum value of about 250PPM is recommended. If the water hardness level in a pool or spa is too low, you can increase it by the addition of Leisure Time Calcium Booster.
The Water Hardness Test Kit will enable you to determine the amount of hardness in your pool or spa water and your tap refill water in just a few minutes.
However, if there is metal contamination in the water, (i.e. copper, nickel or manganese) the solution will slowly approach violet with each addition of solution and never turn blue. This may be an indication of a corrosive condition in the pool or spa due to water imbalance or improper addition of acid. When this occurs the condition should be corrected.