Chemicals serve a variety of functions in your spa. They purify and disinfect the spa water and they help to prevent mineral build-up and damage to the spa's heater pack. Failure to maintain proper pH balance in your spa at all times can cause severe and permanent damage to your spa's heater pack.
A Simple Overview of Spa Chemistry and Disinfecting: The filtering action of your spa's filter can effectively remove soil particles and other debris, but the addition of spa chemicals is required to disinfect your spa. Bromine is the disinfecting agent most commonly used in spas. Bromine products possess strong oxidizing properties, which cause them to react with and destroy many foreign materials other than bacteria.
pH is measured on a scale between 0-4 ppm. pH is a measure of the relative acidity of water. The midpoint of 7 is said to be neutral. In spa water, it is important to maintain a slightly alkaline condition of 7.2 to 7.8. Problems may become severe if the pH range is exceeded or diminished.
In simple terms, alkalinity is the measure of water's "buffering capacity", or its ability to resist changes in pH. Total alkalinity should be in the range of 80-150 ppm. After the total alkalinity is brought within its proper range it should be tested weekly. With high alkalinity, it becomes extremely difficult to balance the pH.
Disinfect Water with Bromine
The most common type of disinfectant is Bromine. The ideal range for bromine is 1.5 to 3.0 ppm. Refer to your test strips to find the level of bromine in your spa. The amount of bromine needed in your spa is dependent upon temperature, the length of time the spa is used, the amount of water in the spa, and the number of people in it.