Pool care has a language all its own. We've provided this glossary to help you understand some common pool care terms. Select a letter below to view a term.
Acid Demand
The amount of acid required to lower the pH and total alkalinity of pool water to the correct level.
Acidity The state of being acidic (corrosive), as opposed to being basic; measuring below neutral 7.0 on the pH scale.
Aggressive Water
A description of unbalanced water that is acidic and attacks and corrodes pool surfaces, fixtures, and pipes.
Algae Microscopic one-celled or multi-celled forms of plant life. They thrive in sunshine. They are present on vegetation, in the air, in soil and in the water. Their microscopic spores are continuously introduced into the pool by winds, dust storms, rain showers, etc. They grow rapidly in pool water when exposed to sunlight and temperature above 40 degrees F. If not destroyed by chemical treatment, they form objectionable slime, heavy build up in the water and odors. They can interfere with proper filtration and greatly increase chlorine demand. Phosphates in the water encourage their growth.
Algaecide
A chemical agent specifically designed and used to kill algae.
Alkalinity
Alkalinity represents the amount of bicarbonates, carbonates and hydroxides in water. It is a measure of the buffering capacity (its degree of resistance to change in pH) of water.
Alum
An aluminum sulfate compound, used (for pools) to cause suspended solids in the water to congeal into filterable masses (flocculate).
Available Chlorine
A rating of a chemical's total chlorine content (oxidizing power) based on a comparison to elemental (gaseous) chlorine having 100% available chlorine.
Bacteria
Invisible single-cell organisms of various forms, some of which can cause infections or disease.
Balanced Water
Water containing just the right amounts of Calcium Hardness, Total Alkalinity, pH and Dissolved Solids so as to prevent scale-forming or corrosive tendencies.
Basicity
The state of being basic (alkaline) as opposed to being acidic; measuring above 7.0 on the pH scale.
Bicarbonate of Soda (baking soda)
The alkaline salt compound (NaHCO3), used to raise TA (Total Alkalinity). Not to be used for increasing pH.
Broadcast
A method of putting granular or powdered chemicals into a pool by spreading them widely over the surface of the water.
Bromine
A sanitizing agent similar in use to chlorine.
Calcium Chloride
A soluble white salt (CaCI2), used to raise the calcium hardness of pool water when required.
Calcium Hardness
A measure of the amount of dissolved calcium in the water. Recommended range is from 200 - 1,000 ppm.
Calcium Hypochlorite
The sanitizing or chlorinating agent, Ca(OCI2), in POOLIFE® Rapid Shock®, POOLIFE® Active Cleaning Granules, POOLIFE® Active Cleaning Caplets, POOLIFE® Power Clean Granules, POOLIFE® Intensive Shock and POOLIFE® TurboShock™;
Chloramines
Compounds formed by combining chlorine with nitrogen compounds from human waste, such as perspiration, urine and skin proteins. Chloramines have an objectionable odor of "too much chlorine" and can irritate swimmers' eyes and cause skin irritation.
Chlorinator
A product that adds available chlorine to pool water.
Chlorine
The one of the five halogen elements most used in various forms to sanitize water. The sanitizing element in POOLIFE® Rapid Shock™ or POOLIFE® Power Clean Granules.
Chlorine - Lock
A term used in the trade to describe a condition where chlorine has slower killing speed on algae, bacteria and burning out organic matter. It is caused by over-stabilization or excess cyanuric acid.
Chlorine Demand
The amount of chlorine required to destroy bacteria, algae and other contaminants in swimming pool water. Once the chlorine demand is satisfied, the water will be in a sanitary condition until further contamination takes place.
Chlorine Residual
See Free Available Chlorine
Clarifier A chemical that helps clear cloudy water, by coagulating small particles in the water into larger groups of particles. This allows them to more easily be removed by the filter.
Combined Chlorine
Chlorine "tied up" or combined with nitrogen compounds in the form of chloramines.
Corrosive Water
A water condition of low pH (acid condition) that can corrode metal pipes, pool fixtures and pumps. Could also etch plaster and cause eye irritation.
Cyanuric Acid
A chemical that has the ability to stabilize chlorine against loss due to sunlight. Cyanuric acid protects the chlorine from ultraviolet light destruction and releases chlorine upon demand. It is the ingredient in POOLIFE® Stabilizer/Conditioner.
Feeder
A device in the circulating water line of the pool, which provides a constant controlled source of chlorine, usually in the form of tablets for the re-circulating water.
Filter
A device in the water circulating line, which screens out solid contaminants by passing the water through a filtering medium. Common media are sand, diatomaceous earth, or cartridges.
Filter Medium
The material in a filter which traps solids which cause cloudy, dirty water.
Floater
A device floating on the surface of the water in the pool containing a supply of chlorine, usually in tablet form, which is fed into the water over a period of time.
Floccing or Floc Treating
Using an agent (I.e., POOLIFE® Clarifier or Alum) which causes suspended solids in the water to congeal into filterable masses.
Free Available Chlorine (FAC) (Also called “chlorine residual” or “available chlorine.”) The amount of active chlorine remaining in the water after the chlorine demand to destroy algae, bacteria, or other contaminants has been satisfied. Recommended level of free chlorine is 1.0 - 4.0 ppm This provides protection against additional contaminants as they may be introduced into the pool.
Halogens
A group of five elements – chlorine, bromine, iodine, fluorine and astatine – the first three of which are the active ingredients in virtually all sanitizer products.
Hardness
The quantity of calcium and magnesium dissolved in water. High levels contribute to cloudy water and scale formation, while low levels cause water to "attack" pool components. Calcium hardness is used for water balance.
High Dissolved Solids
Pool water containing high levels of dissolved minerals. High levels of dissolved solids may cause water to have a "flat" or "salty" taste and cause water to appear dull or "dead". Pools with water three to five years old, or those containing water with solids higher than 3000 ppm should be drained or diluted with fresh water.
Liquid Chlorine
An aqueous solution of Sodium Hypochlorite. Commonly referred to as bleach. Ranges in available chlorine from 3 to 5 % (household bleach) to 10 to 15% (pool or industrial bleach).
Marcite
White plaster finish coat anywhere from 1/8 to 1/2 inch thick applied to the cement or gunite.
Muriatic Acid (Hydrochloric Acid)
A solution of hydrogen chloride (HCl) used to reduce the pH and or total alkalinity of pool water, also used to acid wash concrete, plaster or gunite pools.
OTO
Orthotolidine. A colorless reagent that reacts with chlorine to produce a series of light yellow to deep orange colors which indicate the amount of chlorine in the water. Only measures total chlorine.
Overstabilization
The build-up of cyanuric acid in swimming pool water, which usually results from the extended use of stabilized chlorinators in conjunction with stabilized shock products.
Oxidize To "burn-out" undesirable solids, color and odors.
pH
A measure of pool water acidity and basicity from 1 to 14. A low pH indicates an acid condition which causes swimmer discomfort and can corrode pool plaster and metal equipment. A high pH indicates a basic condition which promotes scale formation and causes cloudy water. The desired pH for pool water is in the 7.2 - 7.8 range.
pH Minus
The POOLIFE™ brand name for sodium bisulfate (NaHS04), also called dry acid. Used to reduce pH and or total alkalinity of pool water.
pH Plus
The POOLIFE™ brand name for sodium carbonate (Na2CO3), also called soda ash. Used to raise pH.
Phenol Red
A dye that is sensitive to pH differences. Turns yellow at acid pH, red-violet at high pH and orange at neutral pH.
Pool Stabilizer
Cyanuric acid. Used to reduce the dissipation by sunlight of chlorine in the pool. (The POOLIFE® brand name for this product is POOLIFE® Stabilizer/Conditioner.)
PPM
Parts per million. The parts by weight of a chemical or mineral per million parts of water.
Precipitate
A solid material which is forced out of solution by some chemical reaction and settles out.
Purity
A state of sanitation attained by proper treatment with disinfectants which destroy dangerous micro-organisms such as bacteria and algae.
Sanitizer
A general term for a substance used as a disinfectant to kill bacteria and algae and oxidize organic contaminants. Also known as Chlorinators.
Saturation Index
A formula using numeric values assigned to each of the five "balanced water" factors to produce an index figure to determine and adjust the balance of swimming pool waters. The five factors are pH, Temperature, Total Alkalinity Calcium Hardness and Total Dissolved Solids. An index result from -0.5 to +0.5 is considered adequately balanced.
Scale
The precipitate that forms on surfaces in contact with water when pH, alkalinity and calcium hardness are too high.
Shock Treatment
The addition of Chlorinators in much larger amounts than normal to eliminate bad water conditions: bacteria, algae, chloramines, colored water.
Skimmer Surface strainer(s) at the overflow or outflow point(s) of a pool, to screen out leaves or other floating debris. It is often used to add chemicals, particularly tablets, to the re-circulating water.
Soda (Baking) See Bicarbonate of Soda
Soda Ash
See Sodium Carbonate.
Sodium Bicarbonate
See Bicarbonate of Soda.
Sodium Bisulfate
Dry acid (NaHS04). The ingredient in POOLIFE® pH Minus. Used to reduce the pH and or total alkalinity in pool water.
Sodium Carbonate
Soda ash (Na2CO3). The ingredient in POOLIFE® pH Plus. Used to raise pH.
Soft Water
Water low in calcium and magnesium mineral content.
Spores Tiny seeds for many forms of plant life, including algae.
Stabilized Chlorine See Isocyanurates.
Stabilized Pool
A pool treated with Cyanuric Acid to reduce loss of chlorine due to sunlight.
Stabilizer See Cyanuric Acid.
Super Chlorination
The practice of adding a sufficient amount of chlorinating compound to water to destroy chlorine demand compounds and any combined chlorine which may be present. Generally, the level of chlorine added is 10 times the level of combined chlorine in the water.
TCCA Trichlorocyanuric acid, trichloro-s-triazinetrione. This is the active ingredient in POOLIFE® Cleaning Tablets and Sticks. Also in POOLIFE® Universal Refillable Cartridge. See Isocyanurates.
Test Kit A kit for testing the factors that determine balanced pool water.
Total Alkalinity (TA) A measure of the total alkaline substances dissolved in the water. If it is too high, pH resists adjustment; too low, pH tends to bounce (very erratically).
Total Chlorine
A measure of "free chlorine" and "combined chlorine" in pool water.
Total Dissolved Solids (T.D.S.) A measure of all solids dissolved in the water. It can cause dull, flat, salty water if too high.
Water Softener
A chemical that exchanges calcium or magnesium for sodium or potassium so that these substances cannot cause "bathtub ring". Not recommended for filling swimming pools.
Winterizing The procedure for leaving the water in the pool over the winter, as opposed to draining. Includes chemical treatment of the standing water, plus physical protection of the pool and its equipment against freezing.
