ACID:

ACID DEMAND: amount of acid needed to lower pH to the proper level for pool water

ACID DEMAND TEST: reagent test usually used in conjunction with a pH test to determine the amount of acid needed to lower pH and total alkalinity levels

ACID RAIN: precipitation having an unusually low pH value (4.5 or lower) caused by absorption of air polluted by sulfur dioxide, carbon dioxide and nitrous oxide

ALGAECIDE: (1) to kill algae; algaecides perform best as a backup to a routine sanitation program (2) help to kill airborne spores as they blow into the pool

ALGAESTAT: retards and prevents algae genesis and growth

ALGAE: (1) microscopic plants deposited in pool or spa water by wind, rain and dust, they thrive in sunlight and warm water, clogging pool equipment and causing slippery surfaces and green water; there are 21,000 known species of algae (2) algae are not disease causing, but can harbor bacteria, and it is slippery (3) most common pool types are black, blue-green, green and mustard (yellow or drawn) (4) pink or red-colored algae-like organisms exist but are bacteria and not algae; maintaining proper sanitizer levels, shocking and superchlorination will help prevent algae occurrence

ALKALI: (1) basic chemical that neutralizes acids by releasing carbonates and/or hydroxides (2) also called base (3) the opposite of acid

ALKALINE: when pool water measures above 7.0 on the pH scale

ALKALINITY: (1) amount of carbonate, bicarbonate and hydroxide compounds in pool water (2) more commonly called total alkalinity (3) measure of the pH-buffering capacity of water (4) also called the water's resistance to change in pH (5) one of the basic water tests necessary to determine water balance

ALUM: aluminum sulfate added to pool water causing suspended particles to sink so they can be filtered or backwashed out

AMMONIA (NH₃): (1) nitrogen-containing compound that combines with free chlorine to form chloramines; chloramines have a strong chlorine odor and can cause skin and eye irritation (2) introduced into the water by swimmers as waste (perspiration or urine) or by other means; quickly forms foul-smelling, body-irritating chloramine - a disabled, less- effective form of chlorine 

ANTI-FOAM: chemical added to the water to make the sud or foam disappears; these products do not remove the source of the sudsing; most often, the water must be drained and refilled to remove the soaps, oils and other causes of foaming; shocking and superchlorination may help prevent foaming

AVAILABLE CHLORINE: see free available chlorine

BACTERIA: single-celled microorganisms of various forms, some of which are undesirable or potentially disease-causing; bacteria are controlled by chlorine, bromine or other sanitizing and disinfecting agents

BACTERICIDE: kills bacteria; chlorine is a bactericide and germicide; silver "algaecides" are actually more bactericide, and are useful on pink "algae"

BAKING SODA: (1) sodium bicarbonate (2) white powder used to raise the total alkalinity of pool or spa water without having much affect on pH

BALANCED WATER: pool water that has a proper pH and the proper mineral content (total alkalinity, calcium hardness) to prevent corrosion and scaling

BASE: see alkali

BASE DEMAND: see acid demand

BIGUANIDE: non-chlorine liquid sanitizer

BLEACH: usually refers to liquid chlorine (sodium hypochlorite 12 percent available chlorine); same chemical used in laundry bleach, but pool chlorine is 12 percent available chlorine while laundry bleach is about 5–6 percent available chlorine

BLUE FINGERNAILS: (1) condition caused by too much copper not chlorine in the pool water; the copper may get into the water by the bad practice of placing trichlor tabs in the skimmer; this acidic product will cause low-pH water, which will in turn dissolve metals in the equipment; the dissolved metal (usually copper) then stains hair, fingernails and, eventually, pool walls (2) can also be caused by keeping the pH too low or misusing acid 

BREAKPOINT CHLORINATION: process of adding sufficient free available chlorine to completely oxidize all organic matter and ammonia or nitrogen compounds; all chlorine added after that point is free available chlorine

BROMAMINES: (1) by-products formed when bromine reacts with swimmer waste, nitrogen or fertilizer (2) active disinfectants that do not smell although high levels are body irritants (3) removed by superchlorination or shock treating (4) a combined bromine-ammonia molecule; unlike chloramines, which are strong smelling and offer no sanitizing properties, bromamine compounds continue to sanitize

BROMIDE: (1) a common term for a bromide salt used to supply bromide ions to the water so they may be oxidized or changed into hypobromous acid, the killing form of bromine (2) used as a disinfectant

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

BROMINE (BR₂): (1) chemical used in various compound forms to sanitize pool and spa water (2) it forms hypobromus acid in water (3) available as a tablet or as sodium bromide, a granular salt (4) member of the halogen family (5) used as a sanitizer in spas, because of its resistance to hot water with rapid pH fluctuations

BUFFER: (1) substance or compound that stabilizes the pH value of a solution (2) water's resistance to change in pH

BUFFERING CAPACITY: ability of the pool to resist changes in pH, which prevents water balance; the buffering capacity is given by the alkalinity, a close cousin to pH; if your pH bounces, or resumes previous levels soon after adjustment, your buffering capacity is too low, check your total alkalinity

BYPASS: (1) arrangement of pipes, gates and valves by which the flow of water may be passed around a piece of equipment or diverted to another piece of equipment (2) a controlled diversion



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