CALCIUM CARBONATE (CaCO₃):

CALCIUM CHLORIDE (CaCl₂): (1) soluble salt added to pool water to raise the calcium hardness level (2) commonly used for snow melting

CALCIUM HARDNESS: (1) amount of dissolved calcium in pool water (too little calcium hardness and the water is corrosive, too much calcium hardness and the water is scale forming)(2) one of the basic water tests necessary to determine water balance

CALCIUM HYPOCHLORITE CA(OCL₂): see hypochlorite

CARBONATE: primary in the make up of total alkalinity and total dissolved solids 

CHELATE: (pronounced KEY-late) (1) process of preventing metals in the water from combining with other components in water to form colored precipitates that stain the pool walls and bottom or produce colored water (2) also called a sequestering agent

CHELATED COPPER: algaecides that contain a special ingredient to prevent the copper from staining the pool walls and bottom or producing colored water

CHELATOR: similar to sequestering agents, a chelating agent is a water soluble molecule that can bond tightly with metal ions, keeping them from coming out of suspension and depositing their stains and scale onto pool surfaces and equipment

CHEMICAL FEEDER: mechanical device that dispenses chemicals in pool water

CHITIN: (1) naturally occurring polymer found in the shells of crabs and lobsters (2) contained in the some proprietary pool products, chitin acts as a coagulant and flocculent for oils, metals and organic materials

CHLORAMINES: substances formed when chlorine combines with swimmer waste causing chlorine odor and irritation to skin and eyes; this compound has little sanitizing value compared to active chlorine

CHLORINATED: see isocyanurate

CHLORINATOR: mechanical or electrical device for dispensing chlorine at a controlled rate; most often a canister or floater filled with tablets of chlorine

CHLORINE (Cl₂): (1) most widely used bacteria-killing agent for pool water; organic chlorine is more suitable than inorganic for pool use because it is generally easier to use, does not affect water balance as much and is non-clouding (2) oxidizes ammonia and nitrogen compounds (swimmer and bather waste) (3) member of the halogen family of sanitizers, its use in swimming pools is in the elemental form of a gas, or as a liquid, granular or tablet compound

CHLORINE FREE AVAILABLE: see free available chlorine 

CHLORINE COMBINED: (1) portion of total available chlorine left over when free available is subtracted (2) measure of chlorine that has already combined with other molecules or organisms, primarily chloramines

CHLORINE TOTAL AVAILABLE: sum of combined and free chlorine levels; with a DPD test kit, one determines free available level, then total available; the difference, if any, is the level of combined chlorine

CHLORINE DEMAND: quantity of free available chlorine removed during the process of sanitizing; the amount of organic and non-organic material contained in the water will "demand" a certain level of oxidizer to be destroyed

CHLORINE ENHANCER: chemical compound that when used in conjunction with chlorine makes the chlorine perform better as an algaecide

CHLORINE GENERATOR: electrical device that generates chlorine from a salt solution in a tank or from salt added to the pool water

CHLORINE LOCK: term that implies that an over abundance of cyanuric acid (stabilizer or conditioner) in the water would cause the chlorine to be all "locked up;" this is not true

CHLORINE NEUTRALIZER: (1) chemical used to make chlorine harmless; used in test kits to counteract the bleaching effect of the chlorine or bromine in order to increase the accuracy of pool water tests (2) sold as chlorine and bromine neutralizer, it is used to destroy excessive amounts of chlorine or bromine, so the high levels will not affect swimmers

CLORINE RISIDUAL: see residual chlorine 

CLARIFIER: (1) also called coagulant or flocculant (2) chemical compound used to gather (coagulate or agglomerate), or to precipitate suspended particles so they may be removed by vacuuming or filtration; there are two types: inorganic salts of aluminum (alum) or water soluble organic polyelectrolytes

COAGULANT: see clarifier

COMBINED CHLORINE: see chlorine combined

CONTAMINANTS: any microparticle or organism, which reduces water clarity or quality, or presents health hazards

COPPER: effective algaestat and algaecide, copper as elemental is used in many pool products

COPPER ALGAECIDE: chemical compound that contains the element copper; too much copper in the water can cause green-colored stains; newer copper algaecides contain an ingredient that prevents the copper from staining but does not affect copper's ability to kill algae; these special copper algaecides are called chelated copper algaecides

COPPER SULFATE: similar to aluminum sulfate, this chemical provides a coagulating and flocculent function in water; used in ponds; this amount of copper would stain swimming pools

CONDITIONED WATER: treated with cyanuric acid or chlorinated isocyanuric to prevent chlorine from being degraded by sunlight

CONDITIONER: see cyanuric acid

CORROSION: etching, pitting, and other destructive erosion of pool surfaces and equipment due to low pH or other chemical imbalance 

CYANURIC ACID: (1) a granular chemical added to the pool water, which provides a shield to chlorine for protection from UV radiation, which disrupts the molecule, destroying its sanitizing ability (2) also called stabilizer conditioner

DEFOAMING: see anti-foam 

DICHLOR: (1) common name for sodium dichlor (2) fast dissolving chlorine compound containing chlorine and cyanuric acid (stabilizer or conditioner); it has a neutral pH and is quick-dissolving, so it can be used for regular chlorination or superchlorination

DIFFUSER: see overdrain

DISINFECT: to kill all pathogenic (disease-causing) organisms

DISINFECTANT: chemicals or processes, which work to destroy vegetative forms of microorganisms and other contaminants; examples are chlorine, bromine, Soft-Swim, ionizers and copper and silver algaecides

DIRT DEMAND: demand that your pool has for dirt; this level is invertedly proportional to available time for cleaning; if you remove the dirt from the pool, you have created a dirt deficit, and the pool will actually suck dirt out of the air to maintain its dirt demand

DISTRIBUTOR: see overdrain 

DPD (Diethyl-P-Phenylene Diamine): a test reagent used to measure the amount of available chlorine in pool water; measures both total and free chlorine 

DRY ACID: (1) sodium bisulfate (2) lowers pH and total alkalinity to proper levels

EFFICACY: (1) power to produce an effect (2) chlorine's efficacy is affected by many factors, including the sun, water balance and the water's chlorine demand

ELECTROLYSIS: (1) electrochemical reaction causing a black stain normally found around metal fixtures or on the plaster; caused by two dissimilar metals being plumbed together or from an improper electrical grounding of pool equipment or lights (2) decomposition of water and other inorganic compounds in aqueous solution by means of electricity; chlorine generators use this principle to produce chlorine from salt in the water

ENZYMES: designed to break down and digest oils