Pool Terms

Swimming pool retailers and consumers alike share the responsibility of knowing how to maintain clean, sparkling water. But for consumers, some of the terminology may be confusing when they walk into a store and realize they haven’t had chemistry in years. Here are some of the most commonly used terms every swimming pool owner should know:

Algicide Products that prevent or control algae growth. The term algicide is used for both algistats and true algicides interchangably.

Bromine A halogen element; brominated compounds provide an alternative primary sanitizer for pools; widely used in spas and indoor pools (Ideal levels are 1.0 – 3.0 ppm for residential pools; 3.0 to 5.0 ppm for commercial pools).

Chlorine Demand The amount of free available chlorine residual needed to destroy organic contaminants and establish a stable residual for effective sanitation. If a pool is unable to maintain or measure a free available chlorine residual, it is likely that the pool has a chlorine demand. This chlorine demand must be satisfied before you can maintain a stable chlorine residual and effectively sanitize your pool. Chlorine demand is measured in the amount of free available chlorine residual needed to destroy the organic contaminants causing your chlorine demand.

Chlorine A halogen element, chlorinating compounds are widely used to sanitize pool water.

Combined Chlorine (Chloramines) Substance formed when free available chlorine combines with urine, sweat or other contaminants. Causes chlorine odor as well as irritation of the skin and eyes. The difference in your Total Chlorine reading and your Free (Available) Chlorine reading is combined chlorine.

Free (Available) Chlorine A form of chlorine compound capable of destroying bacteria and algae. Preferred range: 1.0 to 3.0 PPM.

Halogen A family of elements containing chlorine, bromine, fluorine, iodine and astatine. Halogens are commonly used in a variety of sanitizing situations.

Lint Pump/Pump Pot A bowl-like container located in the plumbing of the pool directly in front of the pump. This container has a basket insert to catch leaves and other debris to prevent them from entering the pump.

Oxidizer A chemical that breaks up contaminants such as suntan oils, cosmetics, perspiration and windblown dirt found in pool water. Oxidizers are used to break down chloramines. Also known as “shock”.

PH A way of measuring the acidity or alkalinity of water. This is the most important part of chemical balance. Proper pH makes swimmers more comfortable, keeps water clear, protects pool surface and equipment, and allows sanitizers to work more efficiently. pH is measured on a scale from 0-14. Preferred range: is 7.4 – 7.6.

PPM Parts Per Million is a unit of measurement for chemical concentration, usually in water.

Sanitizers Products that are added to pool water in order to control bacteria growth.

Saturation Index A value based on water temperature, total alkalinity, calcium hardness and pH. This value predicts the tendency of the pool water to be corrosive, neutral or scale forming.

Shock An oxidizer used in the maintenance of pool water. Eliminates contaminants such as suntan oils, cosmetics, perspiration and windblown dirt found in pool water.

Skimmer A device in a pool wall that continuously removes the surface water and floating debris to be taken away by the filter.

Skimmer Weir A flap-like piece located within the skimmer at the entrance point for water from the pool into the skimmer. The weir provides a dropping surface for water exiting the pool into the skimmer when the water level of the pool is properly adjusted. This dropping surface creates the maximum skimming action, providing for removal of floating debris from the pool surface.

Superchlorination The process involving the adding of chlorinating compound (3 to 5 times the usual dosage) to destroy chlorine demand compounds and combined chlorine.

Total Alkalinity (TA) Total Alkalinity is a measure of pool water’s ability to resist pH change. Total Alkalinity is also measured as part of every BioGuard Insignia and Authorized Dealer’s water analysis. Ideal range is 125 – 150 ppm.

Total Chlorine The sum of free available chlorine (active sanitizing form of chlorine) and combined chlorine (odorous, non-active form of chlorine) present in water.

Water Balance The proper ratio of mineral content and pH that prevents pool water from being corrosive or scale forming. The chlorine and bromine residuals work best in water that is properly balanced. Balanced water is also more comfortable for swimmers and better for equipment. Water balance is determined by making sure that swimming pool water has the appropriate levels of pH (7.4 – 7.6), Total Alkalinity (125 – 150 ppm), and Calcium Hardness (200 to 275 ppm for Plaster & SoftSwim Pools; 175 – 225ppm for all other types).