If you own or manage a pool, you know that in order to keep your pool healthy and safe for swimmers, the water must be balanced. Balanced water is free from harmful bacteria and will not harm eyes or skin. Additionally, balanced water will keep your pool's surface free from algae, staining or corrosion.
In the pool industry, certain guidelines for balancing water are used. These guidelines were established in 1930 by Professor Langelier to provide a balanced water table and are referred to as the Langelier Saturation Index (SI). Four key elements are present and must be kept in balance, including PH, Chlorine, Calcium Hardness and Total Alkalinity. If one or more of these elements is too high or too low, it could lead to harmful conditions that can effect your pool, the swimmers in your pool or both.
Knowing what chemical effect what elements of your water is the key to keeping your pool water healthy. While there is science behind it, it is not rocket science - anyone can learn how to test and treat pool water to achieve ideal water balance.
SPPRC has put together a Water Balancing Guideline that can help. This downloadable PDF lists the elements and what chemicals are used to increase or decrease them.