Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

ACID DEMAND TEST

This is a test used together with a pH test to figure out the amount of acid needed to lower pH or total alkalinity.

ACID DEMAND

The amount of acid needed to bring elevated pH or total alkalinity down to their correct levels which is determined by an acid demand test.

ACID

A chemical substance containing hydrogen which neutralizes alkaline materials. Acid is used to lower the pH or total alkalinity of swimming pool water. The most commonly available forms are hydrochloric acid (muriatic) and dry acid (sodium bisulfate).

AIR BLEEDER

? A device that releases internal trapped air within the system (usually located on the top of the system)

AIR BLEEDING

A terms used to describe the process of releasing the air from a system or tank.

AIR-RELIEF VALVE

A manually operated valve located on the top of a filter tank for relieving the air pressure inside the tank.

ALGAE

Microscopic plant-like organisms that contain chlorophyll. Algae are nourished by carbon dioxide (CO2) and use sunlight to carry out photosynthesis. They find their way into the pool by rain or wind and grow in groupings, resulting in algae blooms. Algae is not known to cause diseases, but provide an ideal condition for bacteria to thrive in. There are tens of thousands of known species of algae. The most common pool types are black algae, blue-green algae, green algae and mustard algae. Pink algae or red algae-like organisms can be found, but are in fact bacteria. Properly maintaining your pool will help prevent algae.?

ALGAECIDE

? A product that kills algae. Algaecides are typically used when your pool is not properly maintained allowing for the growth of algae. Algaecides can be purchased to address certain types of algae such as black or green algae.

ALGAESTAT

, Prevents or slows down the growth of algae. .

ALKALI

Also known as “Base”. An alkali is the opposite of acid and is used to increase the pH or total alkalinity of swimming pool water. Sodium carbonate or sodium hydroxide is used to increase pH and sodium bicarbonate to increase total alkalinity.

ALKALINITY

Also known as Total Alkalinity. A measure of the pH-buffering capacity of water or the water's resistance to change in PH. It is composed of the hydroxides, carbonates and bicarbonates in the water.

ALUMINUM SULFATE

Also known as Alum. This product is used to attract and glob together suspended particles together that are floating in the water. Aluminum sulfate makes the particles that glob together sink to the bottom which makes it easier to vacuum them up.

AMMONIA

(NH3) It is a compound containing nitrogen which, when introduced into the water by swimmers as waste such as urine or sweat excreted from the pores of your skin can combines with chlorine to form foul smelling chloramines, which are usually harmful to our health.

ANTI-FOAM

This is a chemical added to the pool water to reduce the sud-like foam. This type of chemical only reduces the symptom (the foam itself) but does not cure the cause of the foaming.

AUTOMATIC POOL CLEANER

This is a devise that removes debris from the surface of your pool automatically. There are many different types of cleaners that can perform a brushing of the surface also.

AVAILABLE CHLORINE

The amount of free chlorine that is available to sanitize or disinfect the water. It is also referred to as chlorine residual and free chlorine.

BACKFLOW

The back-pressure of water in a pipe in the opposite direction of the intended normal flow.

BACKWASH

This is a reversal of the flow of water to remove the dirt and particulant in the filter system. Backwashing is usually accomplished by the use of a special valve attached to your filter that allows for flow reversal.

BACTERIA

Single cell microorganisms of various forms. Some are pathogens, which can cause infectious diseases. Bacteria are minimized by using chlorine, bromine or other disinfectants.

BACTERICIDE

A chemical additive that kills bacteria.?

BAKING SODA

A sodium bicarbonate powder used to elevate the total alkalinity of pool water with very little affect on pH. It will increase pH up to 8.5, maximum no matter how much used.

BALANCED WATER

This is the goal of your pool chemistry; when you have achieved a perfect chemical balance within the generally accepted parameters.? This includes: pH, total alkalinity, calcium hardness and chlorine levels.

BASE DEMAND

This is a test used to figure out the quantity of a base (alkali) needed to elevate the pH to the specification level.

BASE

Chemicals of alkaline which counteract the pH of an acid. A commonly used base would be soda ash, sodium bicarbonate and sodium carbonate.?

BASECOAT

This is a layer of filter aid between the pre-coat and septum

BLEACH

This is the chemical used in your laundry but it is actually liquid chlorine except that pool chlorine has about three times higher concentration of available chlorine.

BLEACHING OUT

At above 10ppm free available chlorine in a pool, a test kit often shows virtually no chlorine reading because the reagent is being destroyed. If you see an initial pink color which then rapidly fades, you probably have too much residual chlorine in the water.

BLINDING

Filling in and clogging of a filter medium caused by entrapment of particles from a filtered liquid. When the medium becomes "blind," an increase in differential pressure and reduction in flow results.

BOOSTER PUMP

? A pump other than your filtration pump used to increase pumping power over a long distance or to power a pool cleaning system.

BREAKPOINT CHLORINATION

When you shock treat your pool, the goal is to reach a high enough level of free chlorine to break apart all molecular bonds, specifically the combined chlorine molecules, ammonia or nitrogen compounds and to completely oxidize all organic matter. Adding enough chlorine to achieve this is breakpoint chlorination. Any chlorine added past that point is considered free available chlorine.

BROMIDE

This is a bromide salt that when added to water becomes hypobromous acid, the active form of bromine. It is used as a disinfectant in pools.

BROMINATOR

A device for distributing bromine at controlled levels.?

BROMINE

This is a type of sanitizer or disinfectant used to diminish bacteria and algae in swimming pools. It is effective in resisting heat and rapid pH fluctuations.

BUFFER

A chemical which results in resistance to changes in pH.

BUFFERING CAPACITY

The ability of your pool water to resist changes in pH. The buffering capacity is determined by the total alkalinity. If your pH becomes erratic this means the buffering capacity is too low. If your pH rises rapidly, even after the addition of large quantities of acid, the buffering capacity is too high. If the pool has an unstable pH, the total alkalinity should be tested and adjusted.

BYPASS

A configuration of the piping system as to allow for the redirection of the water flow to a different destination.? For example, if the water flow to your waterfall is too great you might redirect a percentage of the water flow to the pool instead.

CALCIUM CHLORIDE

A soluble salt used to increase the calcium hardness level of pool water.

CALCIUM HARDNESS

The content of calcium in your pool water. If the calcium hardness level is too low, the water may be corrosive. If the calcium hardness level is too high, the water may form scale.

CALCIUM HYPOCHLORITE

A compound of chlorine and calcium used as a disinfectant, sanitizer, bactericide, algaecide and oxidizer in your swimming pool water.

CARBON DIOXIDE

This is a gas that when present in your pool water, provides necessary nutrients for the algae to photosynthesis and reproduce in the presence of sunlight. It is also used to lower pH in large pools.

CARTRIDGE FILTER

A filter system that uses fibrous sheets to trap particulant.

CHECK VALVE

? this is a valve that allows water to flow only in one direction.

CHELATED COPPER

Copper algaecides that contain a special ingredient to prevent the copper from staining the pool surfaces. Older pools that used copper plumbing often had issue with the copper sulfates being stripped out of the pipe and distributed onto the pool surface causing a bluish color staining.

CHELATOR

This is an 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

This is a devise that dispenses a set amount of chemicals into your pool water.? A typical chemical feeder would be a chlorine feeder which uses concentrated chlorine tablets placed into a cylinder.? A valve is used to control the water flow into the cylinder thereby adjusting the amount of chlorine distributed into the water system.?

CHLORINATOR

This is a specific type of chemical feeder device used to deliver a set amount of chlorine into the pool water.

CHLORINE (AVAILABLE FREE)

Free available chlorine is active chlorine and is not combined with any other molecule. A portion of the free available chlorine is present as hypochlorous acid, which reacts to destroy organic material in the pool water.

CHLORINE (COMBINED)

The measure of chlorine which has attached itself to other molecules or organisms, typically ammonia or nitrogen compounds. Most of these compounds are present as unwanted chloramines.

CHLORINE (TOTAL)

The sum of combined and free available chlorine levels. With a DPD test kit, DPD1 determines free available chlorine and DPD3 shows total chlorine. The difference, if any, is the level of combined chlorine.

CHLORINE DEMAND

The amount of chlorine necessary to oxidize all organic matter (bacteria, algae, chloramines, ammonia and nitrogen compounds in your pool water.

CHLORINE ENHANCER

A chemical compound used together with that makes the chlorine perform better.

CHLORINE GENERATOR

This is a device that generated chlorine from salt. Also known as a salt system.

CHLORINE LOCK

If the level of stabilizer in your pool water is over 80ppm, the chlorine becomes trapped and is unable to oxidize properly. Despite being able to measure normal chlorine levels, the redox potential is very low, indicating a lack of oxidizer. The only way to fix this is to drain some of the water and refill the pool.?

CHLORINE NEUTRALIZER

A chemical used to deactivate or destroy chlorine. It is used in better test kits to prevent the bleaching effect of the chlorine and consequently to increase the accuracy of the tests.

CHLORINE RESIDUAL

Also called Free Available Chlorine. The amount of chlorine left in the pool water after the chlorine demand has been satisfied.

CHLORINE

A member of the halogen family of sanitizers. Its use in swimming pools is in the form of a gas, as a liquid, in granular or tablet forms. When added to water it acts as an oxidizer, sanitizer, disinfectant and biocidal agent.

CLARIFIER

(also known as a coagulant or flocculent) This is a chemical that coagulates and neutralizes suspended particles in water.

CLARITY

The degree or measure of the transparency of water.

CLINOPTILOLITE

The zeolite that is used as an alternative to quartz as the filter medium in sand filters.

COAGULANT

An organic polyelectrolyte that helps the filter by clumping minute particles together so they can be trapped by the filter.

COAGULATION

The attachment of very small particles turning the combined into one larger glob.

COMBINED CHLORINE

See Chlorine, combined.

COMPENSATION TANK

The tank into which the water from the gutters or skimmer gutters flows. The tank serves to ensure that the pool has enough water to overflow regardless of the number of swimmers and independent of evaporation and splash-out losses.

COMPRESSIBILITY

A measurement of the degree of change in a filter cake when pressure is introduced causing the pressure to change. (This definition applied to pool/spa filtration)

CONDITIONER

Chemically known as cyanuric acid and also called stabilizer. It protects chlorine in the water against the effects of the sun's UV rays.

CONTAMINANTS

The general name for any micro particle or organism which reduces water clarity, quality or presents health hazards. Filtering, oxidizing and sanitizing are necessary to destroy the contaminants.

COPPER ALGAECIDE

A chemical compound that contains the element copper. Most copper algaecides contain ingredients that prevent the copper from staining but do not affect copper's ability to kill algae. These are known as chelated copper algaecides.

COPPER SULFATE

Copper sulfate was one of the original copper algaecides. It is similar to aluminum sulfate in that it provides a flocculent function in water. It can be used in ponds but may harm some aquatic creatures in high concentrations. The amount of copper required to be effective would stain swimming pools.

COPPER

An effective algaestat and algaecide and is one of nature's natural elements. It may also be used in the equipment and plumbing in swimming pools. High levels of copper may stain hair, fingernails or pool surfaces and can also result in green, brown or blue water.

CORROSION

The effects of an acidic pool environment; one in which the pH and/or alkalinity are very low. Corrosion in the form of etching, pitting or erosion of pool equipment and surfaces is the result. May also be caused by misuse of acid or by soft water.

COVER (HARD)

A cover used on pools that rests on the edge of the pool deck and does not come into contact with the water.

COVER (SOLAR)

A floating cover that increases the water temperature by absorption and transmission of solar radiation and reduces evaporation and pollution from the environment.

COVER (WINTER)

A cover that is secured around the edges of a pool when the pool is closed for the season.

CYANURIC ACID

Also called conditioner and stabilizer. A granular chemical added to the pool water which provides a shield to chlorine for protection from the sun's UV radiation. It is also found in dichlor/ trichlor products.

D.E. FILTER

See Diatomaceous Earth Filter

D.E.

Abbreviation for diatomaceous earth. These are the remains of microscopic water plants called diatoms.

DEFOAMER

Also called anti-foam. A chemical added to the water to destroy the foam. These products do not remove the source of the foaming. Shocking and super chlorination may help prevent foaming. Controlled use of certain of the cheaper algaecides can prevent their resulting in foaming.

DIATOMACEOUS EARTH 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 deposits the D.E. on a grid. The D.E. becomes the filter medium.

DIATOMACEOUS EARTH

Also called D.E. A white powder composed of fossilized skeletons of unicellular organisms called diatoms. The skeletons are porous and have microscopic spaces. The powder is added through the skimmer with the pump on and deposits itself on a grid. The powder then becomes the filter medium.

DICHLOR

The common name for Sodium Dichloro Isocyanuric Acid. A quick dissolving chlorine compound made up of chlorine and cyanuric acid (stabilizer) and has a pH of 6.9. Shock treatment with dichlor is not recommended as it may result in over stabilization and chlorine lock. If dichlor is used, a monthly check of the cyanuric acid level is recommended, to prevent over stabilization and chlorine lock.

DIFFERENTIAL PRESSURE

(I) The difference in pressure between two given points. (ii) The combined pressure caused by the debris, filter cake, pre-coat and septum (iii) The effluent pressure minus the influent pressure.

DISINFECT

To kill all pathogenic (disease-causing) organisms.

DISINFECTANT

Chemicals, elements or processes which destroy vegetative forms of microorganisms and other contaminants. Examples are chlorine, bromine, ionizers, ozonators and copper & silver algaecides.

DISSOLVED SOLIDS

See Total Dissolved Solids

DPD

Chemically, NN Diethyl-p-Phenylene Diamine Sulfate. An indicator reagent used to measure free available chlorine (DPD1) and total chlorine (DPD3), bromine, ozone and other oxidizers in water. Far superior to OTO.

DRAIN

A plumbing fitting installed on the suction side of the pump in pools. Also called the main drain, it is located in the deepest part of the pool. Main drains are connected to the pump for circulation, filtration and emptying of the pool.

DRY ACID

Chemically, sodium bisulfate. A dry white crystal that produces acid when added to water. It is used to lower pH and total alkalinity and is safer to handle than liquid acid (hydrochloric acid/ muriatic acid).

EFFICACY

The power to produce an effect. Chlorine's efficacy is affected by many factors, including the sun, temperature, water balance and the water's chlorine demand.

EFFLUENT

Fluid which has passed through a filter.

ENZYMES:

An organic protein, also known as amino acids. Enzymes are non-toxic and biodegradable. Although they are not an oxidizer or clarifier, enzymes significantly reduce cartridge maintenance by breaking down oils into carbon dioxide and water. An ozone purification system is often used to do the work of enzymes.

FEED:

A mixture of particles and fluid that is introduced into the filter. Also a term used to define the pipe that used to deliver the water to its destination.

FIBREGLASS

Fine threads of glass which are available in the form of a rope or a mat. When polyester resins, catalysts and hardeners are applied to fiberglass, it can be formed or molded into pools, water tanks, boats and many other items.

FILL WATER

The water used in filling or topping up the swimming pool.

FILTER AID

This is anything that aids in the separation of particulant from water. D.E. is an example of a Filter Aid.

FILTER AID

A chemical compound added to the water, filter or skimmer that allows the existing filter to become more efficient. They are generally flocculants, coagulants and diatomaceous earth.

FILTER AREA

The total surface area of the filter medium that is exposed to the flow of water from the pump, expressed in square meters.

FILTER CAKE

The combined layers of solids and debris removed in the filtration process and clumped in or on the filter medium.

FILTER CYCLE

The time the filtration system is set to run (on ? off times).

FILTER MEDIUM

The product or material used in the process of water filtrations such as a fibrous material (cartridge filter) and sand (sand filtration).

FILTER POWDER

A common name for diatomaceous earth (D.E.), the filter medium in a diatomaceous earth filter.

FILTER ROCK

Graded, rounded rock and/or gravel which is used to support the sand in sand filters.

FILTER SAND

Sand made up of hard and sharp silica or quartz (or similar), which have been graded for size and uniformity, and is used as the filter medium in sand filters. Nowadays it can also refer to clinoptilolite, the zeolite that is used as an alternative to quartz as the filter medium in sand filters.

FILTER

A devise used to trap particulant (undissolved or suspended particles) in the water.? There are several popular mediums of filtration including D.E., Sand and Cartridge.?

FILTRATE

Water or any fluid that passed through a filter.

FILTRATION RATE

The rate at which a given amount of water can be filtered within the specifications defined.

FILTRATION

The process of filtering water by separating the particulant from water.

FLOCCULATION

An additive that combines and clumps together small particles into larger globs allowing the filter system to more easily trap them.

GALLONS PER MINUTE

is abbreviated with GPM.? It means how many gallons can be delivered in one minute.? An example of this would be your kitchen sink.? If you put a container under the faucet and see how much water you can get into your bucket in one minute, that amount of water would be your GPM. By the way, depending on your water system and where you might live, the average kitchen sink produces about 2 ? GPSs.

GREEN HAIR

A condition caused by too much copper in the pool water or very high levels of chlorine.

GUNITE

A mixture of cement and sand which is sprayed onto the iron reinforced walls and floor of a hole to build a pool. The gunite surfaces are generally plastered.

GUTTER

Also called a Skimmer Gutter. An overflow channel at the edge of the pool through which floating debris, oil and other things flow and empty into the balance tank. Pools with gutters generally do not have skimmers.
gutters generally do not have skimmers.

HALOGENS

The chemical elements in Group VIIB of the Periodic Table of Elements: fluorine, chlorine, bromine and iodine. Only chlorine and bromine are used as oxidizers, disinfectants and sanitizers in swimming pools.

HAND SKIMMER

A net attached to a frame which is then attached to a pole and is used to remove large floating pollutants such as leaves and insects from the water's surface.

HARD WATER

Water that is high in calcium, magnesium or other salts, which makes it difficult for soap to lather. Hard water also has a tendency to form scale.

HARDNESS (CALCIUM)

The amount of calcium dissolved in the water. It is usually measured as calcium carbonate.

HARDNESS (TOTAL)

The amount of calcium, magnesium and other salts dissolved in the water.

HERBICIDE

A chemical compound used to kill or control plant or algae growth.

HYDROCHLORIC ACID

Also called muriatic acid. A very strong acid used in pools to lower the pH or total alkalinity. It can also be used for cleaning an empty pool (acid washing).

HYDROGEN PEROXIDE

An unstable, colorless liquid which is used as an antiseptic in the home. It can be used as an oxidizing agent in pools.

HYDROGEN

The lightest chemical element. It is a component of water and a product of many chemical reactions. pH is a measure of positive Hydrogen ions in water.

HYDROPHILIC

The ability and capacity to absorb liquid.

HYDROPHOBIC

The rejection of liquid; inability to absorb or collect.

HYDROSTATIC COLLECTION TUBE

this s a perforated tub that is connected to the hydrostatic valve.? The tub is placed under the pool to help collect water over a larger area.

HYDROSTATIC PRESSURE

fluid pressure (water) that builds up under your pool.? The water can come from a high water table, underground spring or leaking pipes and poor yard drainage.? This pressure can lift the pool (or a portion of it) out of the ground rendering your pool useless.

HYDROSTATIC VALVE

This is a valve used to protect the pool from damage resulting from hydrostatic pressure.? The valve is spring loaded and will release itself allowing the hydrostatic pressure to be disbursed inside the pool rather that damaging the structure.

HYPOBROMOUS ACID

The active form of bromine in water.

HYPOCHLORITE

The name given to a family of chlorine compounds including: calcium hypochlorite, sodium hypochlorite and lithium hypochlorite. They are used as oxidizers, disinfectants and sanitizers in pool water.

HYPOCHLOROUS ACID

The active form of chlorine in water.

IMPELLER

The rotating part of a pump that is responsible for the movement of water through the pump.

INFLUENT

Dirty or unfiltered water that enters into the filter to the filter.

INLET

A fitting in the pool on the water return line. Water is pumped back into the pool through the inlet after filtration.

IONIZER

A water sanitizer that uses electricity to generate metal ions, usually copper and silver. It works by passing a current through a set of electrodes. The copper is an algaecide and algaestat, while the silver is a bactericide. Ionizers can significantly reduce chlorine consumption. If the ion levels get too high, problems with staining or discoloration of the water occur.

IRON

Iron is a natural element that can cause the water to become clear brown or green in color. It can also result in staining of the pool surfaces. Iron can be controlled by the addition of a suitable sequestering or chelating agent.

ISOCYANURATES

Also called stabilized chlorine. A group of chlorine pool sanitizers that contain stabilizer (cyanuric acid or isocyanuric acid) to protect the chlorine from the UV rays of the sun. The most common types are dichlor and trichlor. The granular form is dichlor, while the tablet or stick form is trichlor (usually used in a chlorine feeder). Stabilized chlorine should be used with care, to avoid problems such as chlorine lock that may be caused by over stabilization.

LANGELIER SATURATION INDEX

Also called Langelier Index or Saturation Index or L.S.I. This index can be used to determine water balance according to the levels of pH, Total Alkalinity, Calcium Hardness and water Temperature. When all the parameters are in balance, the water will neither be corrosive or scaling.

LEAF NET

Also called a Hand Skimmer. A net attached to a frame which is then attached to a pole and is used to remove large floating pollutants such as leaves and insects from the water's surface.

LINER

Also called a vinyl liner. The vinyl membrane that acts as the container to hold the water in one type of pool construction.

LIQUID ACID

Also called hydrochloric acid or muriatic acid. It is used for lowering pH, total alkalinity and for acid washing.

LIQUID CHLORINE

Chemically, sodium hypochlorite. It usually has 12% to 15% available chlorine and has a pH of 13. It is generally cheap, but difficult and dangerous to handle. It also loses its potency rapidly and is usually only used in large commercial pools.

LITHIUM HYPOCHLORITE

A dry granular chlorine compound with 35% available chlorine and has a pH of 10.7. It dissolves quickly and can be used to super chlorinate vinyl-liner pools, painted pools and fiberglass pools.

MAGNESIUM HARDNESS

A measure of the amount of magnesium dissolved in the water. It is part of total hardness.

MAIN DRAIN

This usually refers to the drain that is located in the deepest part of the pool.

MAKE-UP WATER

Also called top up or refill water. It is the water used to replace water lost to evaporation, splash-out, leaks and backwashing.

MARBELITE

Also referred to as Plaster. It is a mixture of white cement and white marble dust used as an interior finish over the gunite or shotcrete of a pool. It can be given a color or it may be left white.

MICRON SIZE

Understood as micrometer which is a unit of measurement equal to 1/1,000,000 of a meter. To give you an idea of size, a single grain of beach sand is equal to about 100 micrometers in size.

MICROORGANISM

An extremely small, living breathing creature. The purpose of disinfectants, sanitizers or oxidizers is to destroy these creatures in the pool water.

MINERAL

Substances such as Calcium, Manganese, Magnesium, Nickel, Copper, Silver, Zinc, Iron, Cobalt or Aluminum. Their presence in high non-chelated concentrations can lead to stains or scale formation. The measure of water hardness is dependent on these minerals.

MULTIPORT VALVE

Also called a 6-way or 6-port valve. Water from the pump can be diverted for various functions by turning the valve handle. The water may: 1. be sent to waste, 2. be used for backwashing, 3. bypass the filter for maximum circulation, 4. filter normally, 5. be used to rinse the filter, or 6. the valve may have all its ports closed. The pump must be off before changing a valve setting.

MURIATIC ACID

Also called liquid acid or hydrochloric acid. A very strong acid used in pools to lower the pH and total alkalinity. It can also be used for cleaning an empty pool (acid washing).

NEUTRALIZER

A chemical used to deactivate or destroy chlorine or bromine. It is used in better test kits in order to increase the accuracy of the pool water tests.

NITROGEN

A gas that causes algae to bloom and disables chlorine. It is introduced into the water by rain and by swimmers. Maintaining proper chlorine levels will prevent nitrogen from becoming a problem. Super chlorination can destroy nitrogen and nitrogenous compounds.

NON-CHLORINE SHOCK

A granular form of potassium peroxymonosulfate (potassium monopersulfate, potassium permonosulfate), used to oxidize materials such as microorganisms, contaminants (ammonia, nitrogen, swimmer waste) or chloramines.

OEM

Abbreviation for Original Equipment Manufacturer or brand name.

ORGANIC WASTE

Also called swimmer or bather waste. Refers to the soap, deodorant, suntan lotion, body oils, sweat, spit, and urine that are introduced into the water by swimmers, as well as the leaves, dust and insects that end up in the pool. The organic waste may form undesirable chloramines, which require large amounts of chlorine or non-chlorine shock to be destroyed.

ORGANIC

Refers to chemical compounds containing carbon atoms bonded together with other elements. The main groups of organic substances found in water are proteins, carbohydrates, fats and oils.

ORP

The abbreviation for Oxidation-Reduction Potential. It is a measurement of the oxidizer’s (e.g. chlorine) ability to oxidize contaminants versus the contaminants' (e.g. algae) ability to reduce the oxidizer. It is an indication of the level of free available oxidizer in the water. ORP is generally used with automated dosage systems and can give a fair idea of the sanitation of the water. It is not a measure of the total or available chlorine. Sometimes called Redox Potential.

OTO

The abbreviation for Ortho Tolidine. A chemical reagent used to test the total chlorine level in water at normal temperatures. It can measure free available chlorine if the water is first cooled to 1