Understanding Water Balance
To have healthy, sparkling pool water requires that your pool water is sanitized and balanced. These two concepts are equally important in creating a pool that you can enjoy. Sanitizing is the process of destroying microorganisms and bacteria – we’ll learn more about this further into the Water Chemistry section.
Balanced water can be defined as being neither corrosive nor scaling. Water continually seeks its own level by dissolving and “holding” minerals until it becomes saturated and cannot hold any more. When this happens, water then seeks to lose its excess material (that which was dissolved).
In a corrosive condition, water is under-saturated and attempts to saturate itself by dissolving everything in contact with it in order to build up its mineral content. This condition causes corrosion and etching – examples of acidic items include orange juice, vinegar, or hydrochloric acid.
In a scaling condition, water is over-saturated and attempts to throw off some of its contents in the form of scale. Scale or carbonates are then deposited on things the water comes in contact with. For example, items that are basic or alkaline include baking soda and antacids.
Simply stated, water balance is a term used to describe the ideal condition of pool water. “Balanced” water has just the right amount of pH, Total Alkalinity, Calcium Hardness and dissolved solids in relationship to its temperature. In more technical terms, The Langelier Saturation Index for calculating saturation is used to determine if the pool water is under-saturated or over-saturated. See the next topic for a technical description of the Langelier Saturation Index.
As water temperature increases, the water balance tends to become more basic and scale-forming. Alternatively, as the temperature decreases, water becomes more corrosive. Although temperature is a factor due to its effect on the properties of water, it is included here. However, relatively speaking, temperature is the least significant factor affecting water balance.