Glossary
of Terms
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ACID: A sour chemical substance that releases
hydrogen ions with the ability to dissolve metals, neutralize
alkaline materials and to combine with bases to form salts. Acid
is used to lower (decrease) pH and total alkalinity of swimming
pool and spa water. Examples are muriatic acid (hydrochloric)
and dry acid (sodium bisulfate). All liquids with a pH lower
than 7.0 are acidic or acid.
AGGLOMERATION: The gathering of fine, suspended
matter in water into “flocs” or larger masses that then can settle
and be filtered from the water.
ALGAE: Microscopic plant-like organisms that
contain chlorophyll. Algae are nourished by carbon and use sunlight
to carry out photosynthesis. They are introduced by rain or wind
and grow in colonies producing nuisance masses. Algae are not
disease-causing but they can harbor bacteria and they are slippery.
There are 21,000 known species of algae. The most common pool
types are black, blue-green, green and yellow or mustard. Pink
or red colored algae-like organisms exist but are bacteria and
not algae. Maintaining proper sanitizer levels, shocking and
superchlorination will prevent their occurrence.
ALGAECIDE: (also algicide) A natural or synthetic
chemical designed to kill destroy or control algae.
ALGAESTAT: (also algistat) Any chemical or
substance that inhibits the growth of algae.
ALKALI: (also called base) A class of compounds
which will react with an acid to give a salt. A substance that
creates a bitter taste and a slippery feel when dissolved in
water. An alkali has a pH greater than 7.0 and is the opposite
of an acid. Alkalis may include the soluble hydroxide, carbonate
and bicarbonate salts of calcium, magnesium, potassium and sodium.
A reaction between an acid and a base is called neutralization.
ALKALINITY: (also more commonly called total
alkalinity) A measure of the pH-buffering capacity of water.
Also defined as the water's resistance to change in pH. Composed
of the hydroxides, carbonates and bicarbonates in the water expressed
in parts per million (ppm) or milligrams per liter (mg/L). One
of the basic water tests necessary to determine water balance.
The ideal range is from 60 parts per million (ppm) to 140 ppm.
AMMONIA: Introduced into the water by swimmers
as waste (perspiration or urine). Quickly forms foul-smelling,
body-irritating chloramines - a disabled, less effective form
of chlorine. See chloramines or combined chlorine.
ANTI-FOAM: A chemical added to the water to
remove suds or foam. These products do not alleviate 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,
superchlorination, clarifiers and enzymes may help remove the
causes.
ANTI-SCALANT: A chemical that inhibits or delays
precipitation and subsequent scale formation.
AVAILABLE CHLORINE: The amount of chlorine,
both free and combined, in the pool water that is available to
sanitize or disinfect the water. Sometimes called residual chlorine.
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BACKWASH: The process of thoroughly cleaning
the filter by reversing the flow of water through it with the
dirt and rinse water going to waste.
BACKWASH RATE: The rate of flow through the
filter media during the backwash cycle, measured in gallons per
minute per square foot (GPM/Sq. Ft.).
BACTERICIDE: A chemical or element that kills
destroys or controls bacteria.
BACTERIOSTAT: A substance that prevents or
retards bacteria growth.
BALANCED WATER: The correct ratio of mineral
content, pH and alkalinity levels that prevents water from being
corrosive or scale forming.
BIOCIDE: Any substance or medium having the
energy to destroy bacteria. Any substance or chemical that kills
or inhibits the growth or microorganisms such as fungi, bacteria,
molds and slimes.
BLACK ALGAE: A stubborn strain of algae that
grows in pools and spas. It can be difficult to remove. See algae.
BLEACH: This term usually refers to liquid
chlorine (sodium hypochlorite, NaOCl, 10-percent to 12-percent
chlorine by weight). It is the same chemical used in laundry
bleach but pool chlorine is 12-percent available chlorine while
laundry bleach is about 5-percent to 6-percent available chlorine.
A gallon of liquid chlorine contains about 1 pound of pure chlorine
or is equivalent to 1 pound of gas chlorine.
BODY OIL: The term used to describe oil from
or on our bodies that gets into the water. Sometimes it refers
to sun tan oil or lotion.
BROMAMINES: By-products formed when bromine
reacts with swimmer waste (perspiration or urine), nitrogen or
fertilizer. Bromamines are active disinfectants and do not smell,
although, high levels are body irritants. Bromamines are removed
by superchlorination or shock treatment.
BROMINE: A common name for a chemical compound
containing bromine that is used as a disinfectant to destroy
bacteria and algae in swimming pools and spas. Available as a
tablet or as sodium bromide, a granular salt.
BROMINE TABLETS: Common name for two chemical
compounds containing bromine. They are used as disinfectants
to destroy bacteria and algae. A separate oxidizer must be used
to destroy swimmer waste.
BROMINATOR: A mechanical or electrical device
for dispensing bromine at a controlled rate. Most often a canister
or floater filled with tablets of bromine.
BROWN ALGAE: A particularly hardy kind of algae
that can look brown but is actually what is called yellow or
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CALCIUM: The presence of calcium in water is
a factor contributing to the formation of scale and is a means
of identifying hard water.
CALCIUM CARBONATE: Crystalline compounds formed
in swimming pool and spa water when the calcium, pH and total
alkalinity levels are too high. Once formed, the crystals adhere
to the plumbing, equipment, pool walls and pool bottom. These
crystals are better known as scale.
CALCIUM CHLORIDE: A soluble white salt used
to raise the calcium or total hardness level in the pool or spa
water.
CALCIUM HARDNESS: The calcium content of the
water. Calcium hardness is sometimes confused with the terms
water hardness and total hardness. Too little calcium hardness
and the water is corrosive. Too much calcium hardness and the
water forms scale. One of the basic water tests necessary to
determine water balance. Minimum level 150 parts per million
(ppm). Ideal range is 200 ppm to 400 ppm.
CALCIUM HYPOCHLORITE: A compound of chlorine
and calcium used as a disinfectant, sanitizer, bactericide, algaecide
and oxidizer in swimming pool and spa water. It is available
as a white granular material usually used for superchlorination
or it is available as tablets used in a feeder for regular chlorination.
It usually contains 65-percent available chlorine but is available
as 70 percent and 75 percent also. Often referred to as cal-hypo.
CARTRIDGE: A replaceable porous element made
of paper or polyester used as the filter medium in cartridge
filters.
CARTRIDGE FILTER: A pool or spa water filter
that uses a replaceable porous element made of paper or polyester
as its removal system.
CHELATE: Pronounced KEY-late. Also called sequester.
It is the process of preventing metals in the water from combining
with other components in the water to form colored precipitates
that stain pool walls and bottoms or produce colored water.
CHELATED COPPER: Copper algaecides that contain
a special ingredient to prevent the copper from staining pool
walls and bottoms or producing colored water.
CHEMICAL FEEDER: Any of several types of devices
that dispense chemicals into the pool or spa water at a predetermined
rate. Some dispense chlorine or bromine while others dispense
pH-adjusting chemicals.
CHLORAMINES: Undesirable, foul-smelling, body-irritating
compounds formed when insufficient levels of free available chlorine
react with ammonia and other nitrogen-containing compounds (swimmer
and bather waste, fertilizer, perspiration, urine, etc.). Chloramines
are still disinfectants but they are a much weaker, ineffective
form of chlorine. Chloramines are removed by super-chlorination
or shock treatment.
CHLORIDE: The ionic, non-killing form of chlorine.
When chlorine in water is reduced or is used up, it becomes chloride
ion in water.
CHLORINATOR: A mechanical or electrical device
for dispensing chlorine at a controlled rate. Most often a canister
or floater filled with tablets of chlorine.
CHLORINE: A term used to describe any type
of chlorine compound used as a disinfectant in swimming pool
and spa water or to kill, destroy or control bacteria and algae.
In addition, chlorine oxidizes ammonia and nitrogen compounds
(swimmer and bather waste).
CHLORINE DEMAND: The amount of chlorine necessary
to oxidize all organic matter (bacteria, algae, chloramines,
ammonia and nitrogen compounds) in the pool or spa water.
CHLORINE ENHANCER: A chemical compound that,
when used in conjunction with chlorine, makes the chlorine perform
better as an algaecide.
CHLORINE NEUTRALIZER: A chemical solution 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. 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. Chemicals
used for this are sodium thiosulfate, sodium bisulfite, sodium
metabisulfite, sodium sulfite, hydrogen peroxide and Vitamin
C.
CHLORINE RESIDUAL: The amount of chlorine left
in the pool or spa water after the chlorine demand has been satisfied.
CLARIFIER: A chemical compound used to gather
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.
Often referred to as a coagulant or flocculent.
CLARITY: The degree of transparency of the
water.
CLOUDY WATER: The visible effect in water created
by material in suspension - also called turbidity. Adding a clarifier
will coagulate the particles and make the filter more efficient.
COAGULANT: An organic polyelectrolyte used
to gather (coagulate) suspended particles in the water.
COMBINED CHLORINE: Undesirable, foul-smelling,
body-irritating compounds formed when insufficient levels of
free available chlorine react with ammonia and other nitrogen-containing
compounds (swimmer and bather waste, fertilizer, perspiration,
urine, etc.). Combined chlorine is still a disinfectant but it
is a much weaker, ineffective form of chlorine.
CONDITIONER: See cyanuric acid.
COPING: The cap or top lip on the pool or spa
wall that provides a finishing edge around the pool or spa. It
can be formed, cast in place, precast or pre-fabricated of extruded
aluminum or rigid vinyl. It may also be part of the system that
secures a vinyl liner to the top of the pool wall.
COPPER ALGAECIDE: A chemical compound that
contains the element copper. Copper sulfate was one of the original
copper algaecides. 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: A chemical prepared from copper
and sulfuric acid. It is one of the oldest algaecides available.
It is also called blue vitriol, blue copperas, bluestone and
cupric sulfate.
CORROSION: The etching, pitting or eating away
of the pool or spa vessel or equipment. Caused by improper water
balance, misuse of acid or acidic products or from "soft" water.
HARD TOP COVER - A cover used on pools, spas
and spas that rests on the lip (coping) of the pool or spa
deck, not a flotation cover, used as a barrier to swimmers and
bathers, for maintenance and thermal protection.
WINTER COVER - A cover that is secured around
the perimeter of a pool, spa or spa and provides a barrier
to bathers and debris when closed for the season.
SOLAR COVER - A cover that, when placed on
the water's surface of a pool, spa or spa, increases the
water temperature by absorption and transmission of solar radiation,
reduces evaporation and prevents wind-borne debris from entering
the water.
CYANURIC ACID: (also known as conditioner and
stabilizer) It protects chlorine in the water from being destroyed
by sunlight. Minimum level 30 parts per million. Too much does
not slow down chlorine activity or effectiveness. It does not
protect bromine from sunlight.
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D. E. FILTER: (also called a diatomaceous earth
filter) A filter designed to use diatomaceous earth (D.E.) as
the filter medium. The D.E. is added through the skimmer when
the pump is on. This deposits the D.E. on a grid, where it then
becomes the filter medium.
DECHLOR OR DECHLORINATE: (also called chlorine
neutralizer) The process of adding a chemical to the water to
remove the residual chlorine. Chemicals used for this are sodium
thiosulfate, sodium bisulfite, sodium metabisulfite, sodium sulfite,
hydrogen peroxide and Vitamin C.
DEFOAMER: (also called anti-foam) A chemical
added to the water to make the suds or foam go away. 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, superchlorination, clarifiers and
enzymes may help remove causes.
DIATOMACEOUS EARTH: (also called D.E.) A white
powder composed of fossilized skeletons of one-celled organisms
called diatoms. The skeletons are porous and have microscopic
spaces. The powder is added through the skimmer and deposits
itself on a grid. The powder then becomes the filter medium.
DIATOMACEOUS EARTH FILTER: (also called a D.E.
filter) A filter designed to use diatomaceous earth (D.E.) as
the filter medium. The D.E. is added through the skimmer with
the pump on which takes the D.E. and deposits it on a grid. The
D.E. then becomes the filter medium.
DICHLOR: A fast-dissolving chlorine compound
containing sodium, chlorine and cyanuric acid (stabilizer or
conditioner). It has a nearly neutral pH (pH 6.8) and is quick
dissolving so it can be used for regular chlorination or superchlorination.
Two types are sold. The anhydrous version provides 62-percent
available chlorine and is more dangerous to store and handle.
The dihydrate, which has 56-percent available chlorine, is much
safer to store and handle.
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ETCHING: Corrosion of the surface of a vessel,
plumbing, equipment or fixtures. Plaster etching is caused by
corrosive or aggressive water, usually because the pH and alkalinity
are too low.
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FIBERGLASS: Fine-spun filaments of glass which
are available in a rope or mat form. When used in a process with
polyester resins, catalysts and hardeners, fiberglass can be
formed or molded into pools, spas and related shapes.
FILL WATER: (also called makeup water) Water
added to a pool or spa to replace water lost due to evaporation,
splash out or drag out.
FILTER: A device that removes undissolved or
suspended particles from water by recirculating the water through
a porous substance (a filter medium or element). The three types
of filters used in pools and spas are sand, cartridge and D.E.
(diatomaceous earth).
FILTER AID: A chemical compound added to the
water or added to the filter that allows the existing filter
to become more efficient. Examples are alum, water clarifiers
and D.E. (diatomaceous earth).
FILTER CYCLE: The operating time between cleaning
or backwashing cycles of a filter. Also, the amount of time the
filter has water flowing through it each day expressed in hours.
FILTER ELEMENT: A device within a filter tank
designed to trap suspended solids as water from the pool or spa
is flowing through it.
FILTER MEDIUM: In essence, the material used
in the filter to trap suspended dirt particles as the water is
flowing through it. The polyester or paper used in making a cartridge
filter element. The sand used in a sand filter. The D.E. (diatomaceous
earth) used in a D.E. filter.
FILTRATION RATE: The rate at which the water
is traveling through the filter expressed in gallons per minute
(gpm) per square foot of filter area.
FLOATER: A chemical feeder whereby the chemical
is placed in a container and the container is allowed to float
around the pool dispensing the chemical. The chemical dissolves
in the floater and is released into the water. Most often these
are used for chlorine or bromine.
FLOC: The clump or tuft formed when suspended
particles combine with a flocculating agent.
FLOCCULATING AGENT: (also flocculant) A chemical
substance or compound that promotes the combination, agglomeration,
aggregation or coagulation of suspended particles in the water.
FLOCCULATION: The combination, agglomeration,
aggregation or coagulation of suspended particles in such a way
that they form small clumps or tufts (called floc).
FOAM: A froth of bubbles on the surface of
the water. Usually caused by soap, oil, deodorant, hair spray,
sun tan oil, etc. that is shed into the water as swimmers enter.
FREE AVAILABLE CHLORINE (FAC): The amount of
free chlorine in the pool or spa water that is available to sanitize
or disinfect the water. FAC is sometimes called residual or available
chlorine.
FREE CHLORINE: The amount of free chlorine
in the pool or spa water that is available to sanitize or disinfect
the water. Free chlorine is sometimes called residual or available
chlorine.
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GAS CHLORINE: A chemical element used as a
sanitizer and disinfectant in swimming pool water. The greenish
gas is compressed and becomes a liquid under pressure. It is
2.5 times heavier than air and is highly toxic to humans if released.
GUNITE: A mixture of cement and sand sprayed
onto contoured and supported surfaces to build a pool. Gunite
is mixed and pumped to the site dry and water is added at point
of application. Plaster is usually applied over the gunite.
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HAIR & LINT STRAINER: Usually a basket
before the pump that is design to catch and prevent hair, lint
and other small material from entering the pump where it may
damage the impeller.
HALOGENS: The chemical elements either individually
or collectively that constitute Group VIIA of the periodic table:
namely, fluorine, chlorine, bromine iodine and astatine. Of these,
only chlorine and bromine are used as disinfectant and sanitizers
in pool and spas.
HAND SKIMMER: A screen attached to a frame
which can be connected to a telepole to remove large floating
debris such as leaves and bugs from the water's surface.
HARD WATER: Drinking water term that indicates
water that contains one grain per gallon - 17.1 parts per million
(ppm) or milligrams per liter (mg/L) or higher of total hardness.
The ideal range of hardness for pools and spas is 200 ppm to
400 ppm.
HARDNESS: The amount of calcium and magnesium
dissolved in the water. "Water" or "total" hardness
refers to the total of the magnesium and calcium dissolved in
the water. Calcium hardness refers to just the calcium. Measured
by a test kit and expressed as parts per million (ppm). Proper
range is 200 ppm to 400 ppm.
HARDNESS INCREASER: A chemical used to increase
calcium or water hardness. It is usually calcium chloride.
HEATER: A fossil-fueled, electric or solar
device used to heat the water of a pool, spa or spa.
HYDROJET: A fitting in the pool or spa on the
water return line from the equipment that blends or mixes air
and water creating a high velocity, turbulent stream of air-enriched
water.
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IDEAL LEVEL OR RANGE: The universally accepted
ranges for the chemical parameters for swimming pool or spa water.
For instance, the ideal pH range is 7.4 to 7.6; the ideal chlorine
level is 1.5 parts per million (ppm) to 3.0 ppm; the ideal total
alkalinity is 80 ppm to 140 ppm depending on the sanitizer being
used; the ideal hardness level is 200ppm to 400 ppm.
IONIZER: A water-sanitation device that uses
electricity to generate metal ions which are dispersed in the
water. It works by passing a low-voltage, DC current through
a set of metallic (usually copper and silver) electrodes placed
in line with the circulation equipment. The copper is an algaecide
while the silver is a bactericide. This process does not remove
swimmer waste.
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JET: (also called a hydrojet or hydrotherapy
jet) A fitting in the pool or spa on the water return line from
the equipment that blends or mixes air and water creating a high
velocity, turbulent stream of air-enriched water.
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LINER: (also vinyl liner) The vinyl membrane
that acts as the container to hold or contain the water in a
swimming pool.
LIQUID CHLORINE: Sodium hypochlorite solution,
chemical formula usually 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. Good for regular
chlorination and superchlorination. It is the same chemical used
for household or laundry bleach except that laundry bleach is
about 5.6-percent available chlorine. One gallon of liquid chlorine
12.5 percent is equal to about one pound of gas chlorine.
LITHIUM HYPOCHLORITE: A dry, granular chlorinating
compound with an available chlorine content of 35 percent. It
is rapid dissolving and should be used to superchlorinate vinyl-liner
pools, painted pools or fiberglass pools as well as spas and
spas.
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MAGNESIUM HARDNESS: A measure of the amount
of magnesium dissolved in the water. It is part of total or water
hardness. It also causes scale if levels are too high. In tap
water, magnesium hardness is about 25 percent of the total hardness
and calcium is about 75 percent.
MAIN DRAIN: Usually refers to a plumbing fitting
installed on the suction side of the pump in pools, spas and
spas. Sometimes called the drain, it is located in the deepest
part of the pool, spa or spa. The Main Drain is unique in
that it does not allow the water to drain to waste but rather
connect to the pump for circulation and filtration.
MAKE-UP WATER: Sometimes called "tap" or "refill" water.
It is the water used to replace water lost to evaporation, splash
out, leaks or swimmer drag out in the pool.
MEDIA: A selected group of materials used in
filters and filter devices to form barriers to the passage of
certain solids or molecules that are suspended or dissolved in
water. Media is the plural form of medium and refers to more
than one type of barrier material. In the pool and spa industry,
filters use either sand, polyester or diatomaceous earth (D.E.)
as the media.
MSDS: Abbreviation for Material Safety Data
Sheet, an informative fact sheet provided by companies that make
and distribute hazardous substances. As part of the Worker Right
to Know Law, an MSDS must be available for each substance and
mixtures of hazardous substances.
MURIATIC ACID: An acid used to reduce the pH
and alkalinity levels in pool water. It is also used in acid
washing, a process that removes stains and scale from pool plaster.
MUSTARD ALGAE: A particularly hardy form of
algae that is yellow colored. See algae.
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NEUTRALIZER: A chemical solution used to make
chlorine or bromine 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. 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. The most
common ones are sodium thiosulfate, sodium sulfite, sodium metabisulfite,
hydrogen peroxide and vitamin C.
NON-CHLORINE SHOCK: A term given to a class
of chemical compounds that are used to oxidize or shock the water
(destroy ammonia, nitrogen and swimmer waste). They contain no
chlorine or bromine and do not kill living organisms. Swimmers
may re-enter the water in only 15 minutes after adding a non-chlorine
shock. Examples are monopersulfates, hydrogen peroxide and percarbonates.
NSPI: Abbreviation for the National Spa & Pool
Institute.
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ORGANIC CHLORAMINES: Chloramines formed from
the combination of chlorine and organic ammonia or nitrogen (swimmer
waste, perspiration, urine, sweat, saliva, etc.) these are not
considered disinfectants like inorganic chloramines.
OXIDATION: To rid the water of ammonia, nitrogen
compounds and swimmer waste (organic compounds). These organic
compounds disable chlorine, are body irritants and have a foul
smell. Removal is accomplished by superchlorination or by shock
treating with a non-chlorine oxidizer.
OXIDIZER: A non-chlorine shocking compound
that removes or destroys built-up contaminants and chloramines
in pool water without raising chlorine levels as required when "superchlorinating."
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PART
PER MILLION: Abbreviated as ppm. It is
a "weight-to-weight" expression. It means one part
in one million parts, such as, 1 pound of chlorine in 1 million
pounds of water or 119,904 gallons.
pH: A term used to indicate the level of acidity
or alkalinity of pool water. Too low pH causes etched plaster,
metal corrosion and eye irritation. Too high pH causes scale
formation, poor chlorine efficiency and eye irritation. Proper
range for pH in swimming pools is 7.4 to 7.6. It is always written
with a lower case "p" and a capital "H."
pH
DECREASER: A chemical that decreases or lowers
the pH of the water. Muriatic acid, dry acid and sodium bisulfate
are examples.
pH INCREASER: A chemical that increases the
pH of the water. Soda ash, sodium sesquicarbonate and sodium
bicarbonate are examples of pH increasers.
pH METER: A sensitive volt meter used to measure
pH via an electrode placed in the water.
PLASTER: A mixture of white cement and white
marble dust used as an interior finish which can be tinted, colored
or left white, applied to the gunite or shotcrete of a pool or
spa.
PUMP: A mechanical device, usually powered
by an electric motor, which causes hydraulic flow and pressure
for the purpose of filtration, heating and circulation of pool
and spa water. Typically, a centrifugal pump is used for pools,
spas and spas.
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QUAT: See quaternary ammonium compounds.
QUATERNARY AMMONIUM COMPOUNDS: (also called
quats) A type of organic compound in which the molecular structure
includes a central nitrogen atom joined by four organic groups
as well as to an acid radical. Cationic quaternary ammonium compounds
adsorb on the cell walls of microbes and algae and react chemically
with the negative charges carried by the cell walls. These chemical
compounds of ammonia are used as algaecides and algaestats.
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REAGENTS: The chemical agents, dyes, indicators
or titrants used in testing various aspects of water quality.
RESIDUAL BROMINE: The amount of measurable
bromine remaining after treating the water with bromine. The
amount of bromine left in the pool or spa water after the bromine
demand has been satisfied. Includes hypobromous acid (HOBr),
hypobromite ion, free and total bromine and all combined bromine.
RESIDUAL CHLORINE: The amount of measurable
chlorine remaining after treating the water with chlorine. The
amount of chlorine left in the pool or spa water after the chlorine
demand has been satisfied. Includes hypochlorous acid (HOCl),
hypochlorite ion free and total chlorine and all combined chlorine.
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SAND: Usually refers to the filter medium used
by a sand filter. The grade most often specified by filter manufacturers
is grade #20 with a particle size of 45 to 55 mm (millimeters).
SAND FILTER: A filter using sand or sand and
gravel as the filter medium. The oldest (patented in 1790) method
of improving water quality, generally using two layers of sand
supported by an underbed layer of gravel.
SANITIZE: To render sanitary; to kill all living
things including bacteria and algae. Similar to sterilize.
SCALE: The precipitate that forms on surfaces
in contact with water when the calcium hardness, pH or total
alkalinity levels are too high. This is the result of chemically
unbalanced pool and spa water. Scale may appear as grey, white
or dark streaks on the plaster, fiberglass or vinyl. It may also
appear as a hard crust around the tile.
SCALE INHIBITOR: A chemical added to the water
that prevents scale from forming.
SCUM: The extraneous or foreign matter which
rises to the surface of the water and forms a layer or film there.
It can also be a residue deposited on the tile or walls of the
pool or spa. Sources of scum are soap, oil, deodorant, hair spray,
sun tan lotion and various others.
SEQUESTERING AGENT: (also called chelating
agent) A chemical that will combine with dissolved metals in
the water to prevent the metals from coming out of solution (precipitating
or causing stains). May also be a chemical that removes dissolved
metals from water.
SHOCK TREAT: The 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 treat used to mean superchlorinating to 10 parts
per millions (ppm) to 20 ppm of free chlorine.
SHOTCRETE: A mixture of sand and cement sprayed
onto contoured and supported surfaces to build a pool or spa.
Plaster is applied over the shotcrete. Shotcrete is premixed
and pumped wet to the construction site.
SILVER ALGAECIDE: Algaecides that have colloidal
silver or silver ions as their active ingredient.
SKIMMER: A device installed through the wall
of a pool or spa that is connected to the suction line of the
pump that draws water and floating debris in from the surface
of the water. The skimmer basket catches large debris while the
filter traps smaller particles.
SKIMMER BASKET: A removable, slotted basket
or strainer placed in the skimmer on the suction side of the
pump, which is designed to trap floating debris in the water
flow from the surface without causing much flow restriction.
SKIMMER WEIR: Part of a skimmer that adjusts
automatically to small changes in water level to assure a continuous
flow of water to the skimmer. The weir has the appearance of
a small floating "door" on the side of the skimmer
that faces the water over which water flows on its way to the
skimmer.
SODIUM BICARBONATE: (baking soda or bicarb)
Used to raise total alkalinity in pool and spa water with only
a slight affect on the pH.
SODIUM BISULFATE: (dry acid) A chemical used
to lower the pH and total alkalinity (2.5 pounds of dry acid
are equal to 1 quart of muriatic acid).
SODIUM BORATE: See sodium tetraborate.
SODIUM BROMIDE: A salt of bromine, used to
establish a bromide "bank" in pool and spa water prior to beginning
the use of bromine tablets.
SODIUM CARBONATE: (common name - soda ash)
A chemical used to raise the pH and total alkalinity in pool
and spa water.
SODIUM DICHLOR: A fast-dissolving, granular,
stabilized organic chlorine compound providing either 56-percent
or 63-percent available chlorine. Used for regular as well as
superchlorination. It also contains an ingredient (cyanuric acid
or stabilizer) that prevents chlorine from being destroyed by
the ultraviolet (UV) rays of the sun.
SODIUM HYPOCHLORITE: Good for regular chlorination
and superchlorination. It is not recommended for spas and does
not contain conditioner or stabilizer to protect it from sunlight,
but it is protected if stabilizer or conditioner is already in
the water. It usually provides 10-percent to 12-percent available
chlorine (or about 1 pound of pure chlorine per gallon); has
a pH of 13; and requires that small amounts of acid be added
to the pool to neutralize the high pH.
SODIUM SESQUICARBONATE: A chemical mixture
of equal parts of soda ash and sodium bicarbonate used to increase
pH and total alkalinity in pool and spa water. It has a pH of
10.1.
SODIUM SULFITE: A chemical used to neutralize,
de-chlorinate or debrominate pool and spa water.
SODIUM TETRABORATE PENTAHYDRATE: White crystals
or powder used to scavenge from water and as a buffer which supplies
alkalinity to water so pH can be more easily maintained.
SODIUM THIOSULFATE: A chemical used to neutralize,
de-chlorinate or debrominate pool and spa water.
SOFT WATER: Water that has a very low calcium
and magnesium content (water hardness) - usually means less than
100 parts per million (ppm) or 6 grains. Also includes water
that has been processed through a water softener. 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 ppm to 200 ppm using calcium chloride.
SOLAR COVER: A cover that when placed on the
water's surface of a pool, spa or spa, increases the water
temperature by absorption and transmission of solar radiation,
reduces evaporation and prevents wind-borne debris from entering
the water.
SOLAR HEATING SYSTEM: Usually panels or coils
of plastic or metal through which water passes to increase the
temperature from the sun's radiant heat.
SOURCE WATER: (also called "tap" water)
The water used to fill or refill the pool or spa.
STABILIZED CHLORINE: A family of chlorine pool
sanitizers that contain conditioner (cyanuric acid or isocyanuric
acid) to protect the chlorine from the degrading ultraviolet
(UV) rays in sunlight. Most common types are sodium dichlor and
trichlor. Granular form is dichlor which is fast dissolving and
can be used for regular chlorination or superchlorination by
broadcasting into the pool or spa. Tablet or stick form is trichlor
which is usually used in a chlorine feeder either the floating
type or the in-line erosion type used for regular chlorination
only.
STABILIZER: (also known as conditioner) See
cyanuric acid.
STAIN: A discoloration or a colored deposit
on the walls or bottom of a swimming pool or spa. Most often
stains are metallic oxides, hydroxides, carbonates, sulfates,
silicates and phosphates of such metals as iron, copper and manganese.
They may appear as green, gray, brown or black.
STAIN INHIBITOR: See sequestering agent.
STERILIZE: To destroy or kill by any of several
means all living microorganisms in water.
SUPERCHLORINATION: The practice of adding an
extra large dose - 5 parts per million (ppm) to 10 ppm - of chlorine
to the water to destroy ammonia, nitrogen and swimmer waste which
can build up in the water. This level of chlorine is required
to destroy all of the combined chlorine in the water, which is
called break-point chlorination.
SUSPENDED SOLIDS: See TDS.
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TAC: Abbreviation for Total Available Chlorine.
It is the total amount of chlorine in the water and includes
both free available chlorine and combined available chlorine.
TDS: (also called Total Dissolved Solids) A
measure of the total amount of dissolved material in the water.
It is comprised of the spent or carrier chemicals added every
time chemicals are added as well as the hardness, alkalinity,
chlorides, sodium, magnesium, calcium, etc. The maximum amount
in a pool is 2,500 parts per million (ppm). Maximum for a spa
is 1,500 over starting TDS. The only way to effectively lower
TDS is to drain part or all of the water and replace it.
TELEPOLE: A long-handled aluminum pole designed
to extend in length. Various pool-cleaning tools such as brushes
or vacuums may be attached.
TEST KIT: An 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. The strips are usually dipped in the water and the resulting
colors of the pads compared to a standard set of colors to determine
concentration.
TITRATION: The method used to test for total
alkalinity and water hardness in swimming pool and spa water.
An indicator reagent is added to a sample and then another reagent
(a titrant) is added until the sample changes color. The drops
or amount of titrant used are equal to the concentration in parts
per million.
TOTAL ALKALINITY: The total amount of alkaline
materials present in the water, also called the buffering capacity
of the water. It is the water's resistance to change in pH. Low
total alkalinity causes metal corrosion, plaster etching and
eye irritation. High total alkalinity causes scale formation,
poor chlorine efficiency and eye irritation. The test measures
for hydroxides, carbonates and bicarbonates.
TOTAL CHLORINE: (also Total Available Chlorine)
The total amount of chlorine in the water. It includes both free
available and combined chlorine.
TRICHLOR: A slow-dissolving, stabilized organic
chlorine compound in tablet form that provides 90-percent available
chlorine. Used for regular chlorination but must be dispensed
using a floating feeder or an in-line feeder (chlorinator). Trichlor
contains an ingredient (cyanuric acid or stabilizer) that prevents
the chlorine from being destroyed by the ultraviolet (UV) rays
of the sun. Trichlor has a 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.
TURBIDITY: Cloudy condition of the water due
to the presence of extremely fine particles in suspension that
can not 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. Turbidity is
measured with a Nephelometer and expressed in units of opaqueness
called NTU (Nephelometer Turbidity Units).
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VINYL LINER: The vinyl membrane that acts as
the container to hold or contain the water.
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WATER BALANCE: Water that has a pH of 7.4 to
7.6, a total alkalinity of 80 parts per million (ppm) to 140
ppm, calcium hardness of 200 ppm to 400 ppm, and a TDS of less
than 2,500 ppm. The water is said to be "in balance" when
the water is within these parameters.
WATER CLARIFIER: (also called coagulant or
flocculent) A 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) and other metals or water-soluble organic
polyelectrolytes.
WEIR: (also called skimmer weir) Part of a
skimmer that adjusts automatically to small changes in water
level to assure a continuous flow of water to the skimmer. The
small floating "door" on
the side of the skimmer that faces the water over which water
flows on its way to the skimmer.
WINTER COVER: A cover that is secured around
the perimeter of a pool, spa or spa that provides a barrier
to bathers and debris when the pool, spa or spa is closed
for the season.
WINTERIZING: The procedure for preparing the
pool or spa for freezing weather. Includes chemical treatment
and physical treatment to protect equipment and vessel - draining,
anti-freeze, drain plugs, etc.
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YELLOW ALGAE: A particularly
hardy kind of algae that is yellow or mustard colored.
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