pH:

PHENOL RED: chemical reagent dye used to test for pH; it can measure pH from 6.8 to 8.4

POTASSIUM PERMONOSULFATE: see non-chlorine shock

POLYMER: (1) substance made of giant molecules formed by the union of simpler molecules; many water clarifiers are made from organic polymers; an example would be polymerized ethylene, called polyethylene (2) algaecide/algaestat made up of repeating polymer molecules; used for green algae and available in varying strengths

POTASSIUM PEROXYMONOSULFATE: (1) active ingredient and chemical name of a non-chlorine shock treatment or non-chlorine oxidizer (2) does not kill bacteria or algae, but it will oxidize or destroy ammonia, nitrogen and swimmer waste; (3) it has a low pH (4) does not increase chlorine or bromine levels the way that superchlorination does (5) reactivates bromine to its killing form, hypobromous acid

ppm: (1) parts per million (2) unit of measurement used in chemical application; it indicates the amount, by weight of a chemical, in relation to one million parts by weight of water (examples: 1 minute in 2 years, 1 inch in 16 miles, or 1 penny in $10,000) (3) equivalent to milligrams per liter (mg/L)

PRECIPITATE: solid particles forced out of solution by a chemical reaction; they may settle to the bottom of the pool or remain suspended in the water 

QUATERNARY AMMONIUM COMPOUND (QUATS): chemical compounds of ammonia used as algaecide and algaestats

QUATS: see quaternary ammonium compound

REAGENTS: chemical agents, dyes, indicators or titrants used in testing water balance

REBAR: (1) reinforcement bar (2) used to add strength to a concrete; after excavation of an in ground pool, a steel cage is formed out of re-bar, and the gunite shell is shot over and surrounding it

RECIRCULATE: this setting bypasses the filter, water coming into the multiport does a U-turn and heads back towards the pool; used only when the filter is broken or when adding specialty chemicals, which specify using this setting

RESIDUAL BROMINE: amount of measurable bromine remaining after treating the water with bromine 

RESIDUAL CHLORINE: (1) amount of measurable chlorine remaining after treating the water with chlorine (2) amount of chlorine left in the pool or spa water after the chlorine demand has been satisfied

RESTRICTED FLOW: condition preventing full flow of water; restriction on the suction side creates higher vacuum, (or suction) while on the pressure side creates higher pressure

SANITIZE: to kill all living things, including bacteria and algae

SANITIZER: chemical agent used to remove unwanted contaminants 

SATURATION INDEX: (1) developed by Mr. Langelier (2) a numerical value used to indicate whether pool water is out of balance (either scale-forming or corrosive); four factors are taken into account: pH, total alkalinity, calcium hardness and water temperature

SCALE: see calcium carbonate

SCUM: (1) extraneous or foreign matter, which rises to the surface of the water and forms a layer or a film (2) residue deposited on the tile or walls of the pool or spa

SEDIMENT: solid material settled out from the water

SEQUESTERING AGENT: see chelate

SHOCK: (1) describes the products used in shocking, such as hypochlorites, potassium permonysulfate or hydrogen peroxide (2) act of bringing the sanitizer level up so high that breakpoint chlorination is reached; when breakpoint is reached, a "shock" is sent through the water, tearing apart molecules and slashing through cell walls

SHOCK TREAT: practice of adding significant amounts of an oxidizing chemical (usually non chlorine oxidizers, such as sodium persulfate or potassium peroxymonosulfate) to the water to destroy ammonia and nitrogen compounds or swimmer waste 

SHOCK TREATMENT: extra large dose of chlorine applied every two weeks or as needed to kill algae and eliminate chloramines in the water 

SODA ASH: (1) sodium carbonate (Na₂CO₃)(2) chemical used to counteract an acidic condition by raising pH

SODIUM BICARBONATE (NaHCO₃): pool additive (baking soda) used to raise total alkalinity

SODIUM BISULFATE: see dry acid

SODIUM CARBONATE (NaHCO₃): see soda ash

SODIUM DICHLOROISOCYANURATE Na(C₃N₃O₃Cl₂): (1) granular organic chlorine that contains 62 percent available chlorine (2) also known as sodium dichloro-s-triazinetrione

SODIUM DICHLOR: see dichlor

SODIUM HYPOCHLORITE (NaOCI): (1) inorganic chlorine in clear, liquid form (2) provides 10 percent to 12 percent available chlorine; has a pH of 13 and requires that small amounts of acid be added to the pool to neutralize the high pH (3) does not contain conditioner or stabilizer to protect it from sunlight, but it is protected if stabilizer or conditioner is already in the water

SODIUM PERSULFATE: (1) active ingredient and chemical name of a non-chlorine shock treatment or non-chlorine oxidizer (2) does not kill bacteria or algae, but it will oxidize or destroy ammonia, nitrogen and swimmer waster (3) does not increase chlorine or bromine levels the way that superchlorination does, so water may be entered in 15 minutes after addition (4) will not reactivate bromine

SODIUM SESQUICARBONATE: (1) chemical mixture of equal parts soda ash and sodium bicarbonate used to increase pH and total alkalinity in pool and spa water (2) has a pH of 10.1

SODIUM SULFITE: chemical used to neutralize or de-chlorinate pool and spa water

SODIUM TETRABORATE: new technology that renders algae incapable of processing carbon dioxide, which they need to live

SODIUM THIOSULFATE: (1) chemical used to prevent false pH readings (2) added to the water sample to remove chlorine prior to testing

SODIUM CARBONATE: see soda ash

SOFT WATER: water that contains less than 100 ppm of calcium and magnesium; pools and spas should never be filled with soft water from a softener; water with less than 100 ppm of hardness should be increased to a minimum of 150-200 ppm using calcium chloride

STABILIZER: see cyanuric acid

STABILIZED CHLORINE: see isocyanurates

STAIN: (1) discoloration or a colored deposit on the walls or bottom of a swimming pool or spa; most often, stains are metals, such as iron, copper and manganese; may appear as green, gray, brown or black; may discolor the water; sometimes a sequestering agent or chelating agent will remove them; if not, usually an acid wash is necessary to remove them from the walls and bottom (2) stains are sometimes confused with scale

STAIN INHIBITOR: see chelate

STRAINER BASKET: second line of defense is a basket at the pump; holes are smaller than those in a skimmer basket, and prevent the pump impeller from clogging

SUCTION SIDE: (1) plumbing prior to and carrying water to the pump (2) under vacuum pressure

SUPER CHLORINATION: see shock treatment and breakpoint chlorination

SURFACTANT: (1) soluble chemical compound that reduces the surface tension between two liquids (2) used in many detergents and soapy cleaning compounds

TANNIC ACID: see tannin 

TANNIN: (1) harmless organic chemical that is leached out of new redwood or cedar hot tubs and is present in some source water (2) also called tannic acid

TDS: see total dissolved solids

TEST KIT: (1) apparatus or device used to monitor specific chemical residuals, levels, constituents or demands in pool or spa water; kits usually contain reagents, vials, titrants, color comparators and other materials needed to perform tests; the most common pool and spa water tests are: pH, total alkalinity, free available chlorine, water hardness, cyanuric acid, iron and copper

TEST STRIPS: small plastic strips with pads attached that have been impregnated with reagents that can be used to test pool water for residuals, levels, constituents or demands; usually dipped in the water, and the resulting colors of the pads are compared to a standard set of colors to determine concentration

TITRATION: method of testing pool water for calcium hardness and total alkalinity

TOTAL ALKALINITY: (1) amount of alkaline bicarbonate in pool water (2) acts as a buffer to prevent fluctuations in pH

TOTAL CHLORINE: total amount of chlorine in the water; includes both free available and combined chlorine 

TOTAL DISSOLVED SOLIDS: (1) measure of the total amount of dissolved material in the water; maximum amount in pools is 2500 ppm, maximum in spas is 1500 over starting TDS; the only way to effectively lower TDS is to drain part or all of the water and replace it (2) also called TDS

TRICHLOR: (1) slow-dissolving, tableted or granular, stabilized organic chlorine compound providing 90 percent available chlorine (2) used for regular chlorination but must be dispensed using a floating feeder or an in-line feeder (chlorinator) (3) contains an ingredient (cyanuric acid or stabilizer) that prevents the chlorine from being destroyed by the ultraviolet (UV) rays of the sun (4) pH of 2.8, and regular trichlor tabs should not be placed in the skimmer, as the low pH will corrode the metal components in the equipment

TRICHLOROISOCYANURATE (C₃N₃O₃Cl₃): (1) organic chlorine available in compressed tablets or sticks, containing 90 percent available chlorine (2) also known as trichloro-s-triazinetrione

TURBIDITY: cloudy condition of the water due to the presence of extremely fine particles in suspension that cannot be trapped by the filter because they are too small; adding a clarifier, such as an organic polymer or alum, will coagulate the particles and make the filter more efficient

ULTRA VIOLET LIGHT TREATMENT: using UV wavelength radiation to destroy contaminants in water; UV light is also used to create ozone molecules for the same purpose

V: element that combines with chlorine to form chloramines, which causes swimmer irritation and chlorine odor

VISION SYSTEM: technology, which isolates nascent oxygen into a powerful sanitizing tool