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glossary of pool terminology



ACID - a chemical used to lower pH and or alkalinity of the pool water. Most commonly used acids are liquid (Hydrochloric Acid) or dry (Sodium Bisulphate).

ACID DEMAND - the amount of acid required to bring high pH and total alkalinity down to their proper levels. Determined by the Acid Demand Test.

ACID WASH - procedure using an acid solution to clean the interior surface of a swimming pool.

AGGREGATE - major component of plaster, composed of sand, marble dust, pebbles and other solid material.

AIR BLOWER - a mechanical device that forces air through holes in the floor, bubbler ring or hydrotherapy jets in a spa.

AIR BLOWERS - a mechanical device that forces air through holes in the floor (air grid) of a spa to produce bubbles.

AIR SWITCH - a pneumatic control device used to operate pool and spa equipment safely. A button located near the water and convenient for use is pushed which sends air pressure through a small flexible tube or hose to a switch.

ALGAE - plant organisms, which grow at a rapid rate to discolour the pool water and interior finish.

ALGACIDES - products/chemicals used to prevent or control algae growth, available in many forms and types. These products are a supplement to your sanitiser and are specifically intended to kill all forms of algae. Warning- check with your local pool shop / maintenance person prior to purchase for compatibility with your pool maintenance systems.

ALKALI - a chemical with a pH above 7.

AMPERAGE - (amps) the term used to describe the strength of an electrical current. It represents the volume of current passing through a conductor in a given amount of time. Amps=watts/volts.

ANGLE OF REPOSE - the maximum slope or angle at which a material, such as soil, remains stable without falling or sliding.

ANODE - the electrode (positive) that attracts negatively charged anions. The positive pole of an electro-dialysis system.

ANTI-VORTEX DRAIN COVER - a cover or grate attached to the main drain that prevents a vortex (whirlpool) from forming as the water passes through it.

AUTOMATIC CONTROLLER - a device that automatically executes the decision making necessary to determine the proper adjust of a chemical parameter. Controllers are currently capable of automatically adjusting pH and sanitiser levels in water.

AUTOMATIC POOL CLEANER - pool maintenance system that will agitate or vacuum debris from the pool interior.

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.


BACKFILL - The repositioning of the soil after construction of a pool, refilling an excavated area.

BACKFLOW - T he backing up of water through a pipe in the direction opposite to normal flow.

BACKFORM - Shoring required below ground level when the soil caves in.

BACK PRESSURE - Resistance to flow, normally expressed in pounds per square inch (psi).

BACKWASH - The process of thoroughly cleaning a sand filter by reversing the flow of water through he filter to flush out any dirt, going to waste, (legal point of discharge).

BALL VALVE - Simple non-return valve consisting of a ball resting on a cylindrical seat within a liquid passageway.

BEAM - The beam is the lip located around the top of the swimming pool shell to support the pool coping, usually constructed of concrete and reinforced with steel rods.

BLOWER - An electrical device that produces a continuous rush of air to create the optimal bubbling effect in a spa, hot-tub or whir-pool. It is usually plumbed in with the hydrotherapy jets or to a separate bubbler ring.

BOND BEAM - The top of a wall or spa that is built stronger than the wall so it will support the coping and surrounding deck.

BOOSTER PUMP - A water pump added to a spa circulation system to add pressure to the jets. Also used for some automatic pool cleaners.

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. Most commonly used in spas because of its tolerance to hot water.

BROMINATOR - A mechanical or electrical device for dispensing bromine at a controlled rate. Most often a canister or floater filled with tablets of bromine.

BUFFER - A substance or compound that stabilises the pH value of a solution. Its also the waters resistance to change in pH. An alternative name for sodium bicarbonate which is used to raise pH and total alkalinity.

BUILDING SURVEYOR - An individual or company responsible for making sure a building is safe and that it complies with Current Building Regulations. Surveyors evaluate and assess plans, conduct inspections and issue building permits, as well as checking that building practitioners are registered and carry appropriate insurance.

BYPASS - An 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; a controlled diversion.


CALCIFICATION - The formation of calcium carbonate on the walls or pipes, or in a heater due to the precipitation of calcium carbonate.

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 is scale forming. One of the basic water tests necessary to determine water balance. Minimum level 150ppm. Ideal range Is 200-400ppm.

CARTRIDGE FILTER - A swimming pool and spa water filter that uses a replaceable porous element made of paper or polyester to remove even the finest particles without embedding them in the filter.

CATHODE - The negative electrode that attracts positively cations. The negative pole of an electrolytic system.

CAULKING MATERIAL - Material (usually silicone) used to fill a gap in a joint and provide a waterproof seal.

CAVITATION - The formation of partial vacuum when pump capacity exceeds water replacement supply. The formation and sudden collapse of vapour bubbles in a liquid, usually resulting from low local pressures, as on the trailing edge of a propeller.

CHECK VALVE - A mechanical device in a pipe the permits the flow of water or air in one direction only.

CHEMICAL BALANCES - A composite term covering those aspects of water which should be adjusted to achieve water suitable for swimmers, sanitisers and the pool surface and equipment. Pool water is chemically balanced when the pH, Total Alkalinity and Calcium Hardness levels are within certain parameters.

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.

CHLORINATION - The adding of chlorine to the pool water.

CHLORINATOR - A mechanical or electrical device for dispensing chlorine at a controlled rate. Normally of three forms:

  • SALT WATER CHLORINATOR - a unit which manufactures chlorine through the electrolytic conversation of salt. Chlorine levels will depend on several variables including running time of the unit.
  • CHLORINE CONTROLLER - a machine which feeds liquid chlorine into the pool water. Normally integrated with the filtration cycle, these units have electronic control on chlorine.
  • EROSION FEEDER - a canister or floater containing solid tri-chlor tablets which dissolve in the water, these units control the rate of chlorine addition through a manual valve which varies the water flow over the tablets.

CHLORINE - A term used to describe any type of chlorine compound used as a disinfectant in swimming pool and spa water to kill, destroy or control bacteria and algae. In addition, chlorine oxidisers ammonia and nitrogen compounds (swimmer and bather waste). It is pH dependent. There are many different types available. Check with your pool shop and or maintenance person for the most suitable for your pool.

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

CHLORINE DEMAND - Amount of chlorine required to kill all the pollutants in the swimming pool water.

CLOUDY WATER - The visible effect in water created by material in suspension. A condition of the water due to the pressure 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.

CLARITY - How clear the swimming pool water is- degree of transparency of the water.

COMBINED CHLORINE - Chlorine which has combined with nitrogen based compounds to form chloramines. Associated with very strong chlorine like smell, this compound is a pool sanitiser and indicates the need for more chlorine.

COMMISSIONING - To start up the pool once construction is completed and the pool has been filled with water. This involves adding chemicals to adjust the water balance and turning on the pool equipment.

CONCRETE POOLS - A swimming pool constructed of concrete and reinforced with steel.

CONTROLLER - A device that automatically executes the decision making necessary to determine the proper adjust of a chemical parameter. Controllers are currently capable of automatically adjusting pH and sanitizer levels in water.

COPING - The walkway immediately surrounding the swimming pool or spa that provides a finished edge between the pool structure and the surrounds. Some popular finishes include terra-cotta, bricks, sandstone or bluestone type pavers, and timber decking.

COUPLING - A plumbing fitting that is used to connect two pieces of pipe.

COURTYARD POOL - A smaller sized swimming pool that can be located in more diminutive spaces.

CYANURIC ACID - (also known as conditioner and stabilizer) chemically, conditioner is cyanuric acid, chemical formula. It protects chlorine in the water from being destroyed by sunlight.


DATUM POINT - A point used to establish the finish level of the swimming pool, usually a fixed Reference point on site ie. House floor level, surveyed RL etc.

DIAMETER - The length of a straight line measured through the centre of a circle from one side to the other.

DISSOLVE - The separation into component parts creating a process of solid particles mixing with a liquid and then taking on the appearance of the liquid. Like mixing sugar into water.

DIVERTER / THREE WAY VALVE - A plumbing fitting used to change the direction or re-direct the flow of water. Some diverter valves are used on pool/spa
combination to allow the use of the spa and then switch the flow back to the pool.

DOSING SYSTEM - A liquid chlorine feeder that is designed to automatically inject chlorine Into the swimming pool at regular intervals throughout the filtration cycle.

DRAIN - This term usually refers to a plumbing fitting installed on the suction side of the pump in pools, spas and hot tubs. Sometimes called the main-drain, it is located at the deepest part of the pool, spa or hot-tub. It is not a drain, such as a drain on a kitchen sink. Main drains can allow the pool to drain to waste, but usually connect to the pump for circulation and filtration.


EXPOSED AGGREGATE - A pebble-type interior finish made from a blend of ingredients including White cement, quartz sand, metallic oxides and coated aggregate. Exposed aggregate provides A smooth surface and is available in a range of colours.


ILTRATION - The process of passing the pool water through the filter medium to remove dirt and debris particles.

FILTER- A device that removes undisclosed or suspended particles from water by recirculation the water through a porous substance (a filter medium or element). The three types of filters used in swimming pools and spas are sand, cartridge 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 SAND - A type of filter media composed of hard, sharp silica, quartz or similar particles with proper grading for size and uniformity. The most common grade used is No. 20 in sand filters.

FINISH CONCRETE LEVEL (FCL) - The level of the finished pool structure.

FLOW RATE - The quantity of water flowing past a designated point within a specified time, such as the number of litres flowing past a point in one minute - abbreviated as lpm.

FORMWORK - Generally built on-site out of timber and plywood, the formwork provides a solid surface for the steel to be fixed against and the concrete to be sprayed against. Once the concrete has set (or cured), the formwork is stripped away (removed) to expose the finished shape of the concrete swimming pool.

FREE AVAILABLE CHLORINE - That portion of chlorine in the pool water available to oxidise contaminants as opposed to ‘Combined Chlorine’ or ‘Total Chlorine’.


GEOMETRIC POOLS - A geometric pool has even lines and features. Usually built in a rectangular shape, this pool is considered the ‘traditional’ swimming pool style.

GROUT - A thin, coarse material used to seal joints like those between tiles. Grout is generally composed of a mixture of water, cement, sand and sometimes colour tint which is applied as a thick liquid and hardens over time.

GUTTER - An overflow trough at the edge of the swimming pool through which water and debris flow. A gutter is needed when a pool has a wet-edge design.


HAIR AND LINT POT - Used to trap finer particles that manage to pass through the skimmer box basket. This section of the circulating pump contains the secondary strainer basket for the filtration system. It requires regular cleaning.

HANDOVER - A meeting between pool builder and owner upon completion of the project to discuss the operation Of the swimming pool/spa, and to review equipment procedures and correct chemical balances.

HAND RAIL - A tubular steel or plastic device that can be gripped by swimmers or bathers for the purpose of steadying themselves. Usually located near the steps in the pool.

HARDNESS INCREASER - A chemical used to increase calcium or water hardness. It is usually calcium chloride.

HEAD - A measure of pressure at a given point in a water system, expressed as pounds per square inch (psi), or the height of a column of water that would produce the pressure.

HEADER - A manifold in the heater that directs flow of water into and out of the heat exchanger.

HEAT EXCHANGER - A device located inside the heater providing for the transfer of heat from the heat source of the water. This is usually a series of metallic tubes with fins located just above the flames.

HEAT PUMP - A refrigeration compressor, usually electrically driven, that is operated in reverse. To obtain heat, the evaporator side (cooling coil) is exposed to water, air or ground. The coil transfers the heat from this source to the condenser coil, where it discharges the heat to the water in the pool or spa.

HEATER - A fossil-fuelled, electric or solar devise used to heat the water of a pool, spa or hot-tub.

HIGH RATE SAND FILTER - A filter using sand for the filtration media designed for flows in excess of 5GPM but less than 20GPM per square foot.

HORSEPOWER - Work done per unit of time. One horsepower equals 33,000 foot pounds of work per minute or approximately 746 watts. Motors for pumps are rated in horsepower.

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 or air-enriched water.

HYDROCHLORIC ACID - A very strong acid used for various cleaning needs. Used in ‘acid washing’ a pool. Use extreme care in handling.

HYDROSTATIC PRESSURE - The force created by the water that tends to push pools up out of the ground.

HYDROSTATIC RELIEF VALVE - A spring loaded plug situated in the main-drain bowl designed to open if the water pressure under the pool is greater than the water pressure within the pool. A relief valve reduces the possibility of an empty pool lifting out of the ground.


IMPELLOR - An open or closed disc attached to the motor shaft which forces water through the filtration system.

INDOOR POOL - A swimming pool located inside a house or other dedicated structure.

INFLOOR CLEANING SYSTEM - A programmed in-floor cleaning and circulation system that cleans a swimming pool automatically. Pop-up nozzles built into the floor of the swimming pool use high pressure streams of water to push dirt, sand, leaves and debris from every corner toward the MDX drain, where it is removed into a collection basket or canister for ease of disposal.

INLET - A fitting in the pool or spa on the water return line from the equipment that water returns to the pool. Usually the last thing on the return line.


LAP POOL - Lap pools are built so that people can swim laps for health and fitness. Lap pools tend to be long and narrow, usually over 15 metres long.

LEAF BASKET - A strainer basket situated in the skimmer box to trap large leaves and debris before they enter the hair and lint pot.

LEAF RAKE - Contains a net and are used to remove the leaf and other debris from the pool. The leaf rake shank fits into the telepole and clips in place.

LETTER OF APPOINTMENT - A document required by the building surveyor to confirm that a swimming pool construction company is applying for a building permit on behalf of the property owner. This is also called an ‘owners consent form’.

LICENSED ELECTRICAL & PLUMBING - Electrical and plumbing connections are not usually included in a swimming pool costing and or contract because they require work by licensed tradesman. An electrician will be needed to install switch wires for pool lights, water features etc and provide power and power points to the plant room / location. A plumber will be needed to make connections for the backwash, cold water supply and gas (if applicable).

LIGHT NICHE - The area in the pool or spa that houses the underwater light.

LIQUID CHLORINE - A sodium hypochlorite solution. Usually provides 10 to 12% 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 fro regular chlorination and super chlorination.

LOAD BEARING - A load-bearing wall is one in which the wall of a structure bears the weight and force resting upon it. Swimming pool walls can be load bearing if a planter box, for example, is being supported by part of the concrete shell.

LPM - Litres per minute (lpm).


MAIN DRAIN - This term usually refers to a plumbing fitting installed on the suction side of the pump in pools, spas and hot tubs, and is located at the deepest part of the pool-can be used to drain the swimming pool.

MANIFOLD - The branch pipe arrangement that connects several input pipes into one chamber or the chamber into several output pipes. A filter manifold connects several input pipes from the filter septa back into one common pipe.

MECHANICAL SEAL - A mechanical device or assembly that forms a seal between a pump Casing and a rotating shaft to prevent leakage along the shaft.

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.

MICRON - A unit of length equal to one millionth of a meter- it is .0000394 inch. Microns are used to describe the pore size of filter media. Sand filters have openings of 25-30 microns; cartridge filters have openings of 8-10 microns; and D.E (diatomaceous earth) filters have openings of 1-3 microns. Humans, without magnification, can see objects 35 microns or larger. A granule of table salt is between 90 and 110 microns. Abbreviated as m m.

MULTIPORT VALVE - Also called a rotary-type backwash valve. This valve replaces as many as six regular gate valves. Water from the pump can be diverted for various functions by merely turning the valve handle. The water may be sent to waste, used for backwashing, bypassing the filter for maximum circulation, for normal filtration, filtering to waste (rinse), or the valve may be closed to not pass water. The pump must be off before changing a valve setting.


NICHE - the housing built into the wall of a pool or spa to accommodate a light fixture.


ORGANIC WASTE - Also called swimmer or bather waste- all of soap, deodorant, suntan lotion, lipstick, makeup, cologne, body oils, sweat, spit, urine etc. brought into the water. They also form chloramines, which are foul-smelling and body irritants. Require large amounts of chlorine or non-chlorine shock to destroy.

O-RING - A round, circular rubber-material gasket shaped like the letter O that is used to seal around round objects, such as the ends of two pipes.

OVERFLOW SYSTEM - A system for the removal of pool surface water through the use of Overflows, surface skimmers, and surface water collection systems.

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.

OZONATOR - Electrical devices which produce ozone from air oxygen used for oxidation of water contaminants. Corona Discharge or CD ozone is produced by a discharge of electricity at ranges from 1 to 7 percent ozone in air. Ultraviolet or UV ozone is produced by a UV light or lamp at ranges from .001 to .01

OZONE - A gaseous molecule comprised of three atoms of oxygen. It is generated on site From air oxygen and used for oxidation of water contaminants.


PART PER MILLION - 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 one million pounds of water or 119,904 gallons. Many of the common pool water tests as well as acceptable ranges are stated as ppm. For instance, Free Available Chlorine should be kept between 1.0 and 3.0 ppm; Total Alkalinity should be between 80 and 120 ppm; and Water Hardness should be between 200 and 400 ppm. A ppm and a milligram per litre (mg/L) are considered equal.

PERIMETER - The distance around the outer edge of a shape.

pH - A measure of the alkalinity (above 7.0) or acidity (below 7.0) of pool water. The slightly alkali range of 7.2 to 7.8 is recommended. The only acids which should be used to lower pH are Hydrochloric Acid or Sodium Bisulphate.

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.

PHENOL RED - A chemical reagent dye used to test for pH. It can measure pH from 6.8 to 8.4

PLASTER / RENDER - A mixture of white cement and sands used as an interior finish which can be tinted, coloured or left white, applied to gunite or shotcrete of a pool or spa.

PLUNGE POOL - A plunge pool is small in diameter, but deep.

POOL BRUSH - Wall and floor brush is used to remove the dirt, stains and other material sticking on the interior surface. Made of either nylon bristle or wire with a shank that fits the telepole.

PPM - Abbreviation for parts per million (ppm).

PRE-DILUTE - To dilute a chemical before adding it to the pool or spa water.

PRELIMINARY WORKS AGREEMENT - A preliminary contract document that allows the pool builder to start administration work on the project before all the details have been finalised in the SPASA contract.

PRESSURE - The force pushing on a unit area. Water pressure is normally measured in pounds Per square inch (psi) or feet of head.

PRESSURE GAUGE - A gauge with an analog dial indicating the pounds per square inch (psi) of pressure that has built up within a closed container, such as a filter.

PRIMARY PLUMBING - The pipe work that makes up the internal circulation system of the pool. These pipes are laid out and configured prior to the concrete poor.

PRIME - To fill a pump casing or siphon with water to remove air. Most pumps must be primed before start-up or they will not pump water.

PROPERTY PROTECTION WORKS - This usually involves underpinning or some other form of foundation works to protect the neighbouring property from being undermined.

PSI - An abbreviation for pounds per square inch.

PUMP - A mechanical device, usually powered by an electrical motor, which circulates water from the pool where water is drawn into the filtration system.

PUMP CAPACITY - The volume of liquid a pump is capable of moving during a specified period of time. This is usually litres per minute (lpm).

PUMP CURVE - A graph that represents a pump’s water flow capacity at any given resistance. (also called a pump performance curve).

PUMP LINT POT - Or Pump Strainer Basket- a device placed on the suction side of the pump, which contains a removable strainer basket designed to trap debris in the water flow without causing much flow restriction. Sometimes called a ‘hair-and-lint trap’.

PVC - Abbreviation for Poly Vinyl Chloride. An artificial polymer made from vinyl chloride monomer used in pipes for swimming pools and spas.

PVC PIPE - A type of pressure pipe for water distribution manufactured from poly vinyl chloride compound used to plumb swimming pools and spas.


RADIUS - The distance from the centre of a circle to its edge; one half of the diameter.

RATE OF FLOW - The quantity of water flowing past a designated point within a specified time; such as the number of litres flowing past a point in one minute - abbreviated as lpm.

RE-BAR - Reinforcement bar, used to add strength to concrete. After excavation of an in-ground pool a steel Cage is formed out of re-bar, and the concrete shell is sprayed over and surrounding it.

RENDER - A mixture of sand and cement used on the interior of a pool or spa to smooth out the surface before tiles or exposed aggregate (pebble) are applied.

RETURN INLETS - Part of the plumbing circulation system to return filtered water back to the swimming pool.


SALT CHLORINATOR - A unit which manufactures chlorine through electrolytic conversion of salt. A saltwater pool is not actually chlorine free; it simply utilises a chlorine generator instead of direct addition of chlorine.

SALT WATER - Water containing relatively high concentration of salt, usually over 1,000 ppm but less than the sea. The ocean has about 35,000 ppm.

SAND - Usually refers to the filter medium used by a sand filter.

SAND FILTER - A filter that operates on the basis of ‘depth filtration’; dirt is driven through the sand bed and trapped in minute spaces between the particles of sand.

SANITISE - To render sanitary: to kill all living things, including bacteria and algae.

SCREENINGS - Crushed rock/screenings which acts as a drainage layer between the ground and the swimming pool shell.

SEAL - Packing gland material or a mechanical device that fits around a pump shaft and prevents either air intake to the pump or water leakage.

SECONDARY PLUMBING - The system of PVC pipes that run underground from the swimming pool structure to the Designated equipment location - plant room.

SELF-PRIMING - A classification given to centifrugal pumps that indicates the pump is capable of Operating above the pool water level after initially filling with water. Most self-priming pumps have a hair and lint strainer basket/pot attached to the front of the pump.

SENSOR - An electrical or electronic device that measures water quality. Examples are pH electrodes, pH meters, ORP (Oxidation Reduction Potential) probes and meters, TDS meters and probes.

SET OUT - The swimming pool is marked out on the property to show the exact location and shape in preparation for excavation.

SHOCK TREATMENT - The practice of adding significant amounts of chlorine or similar product- an oxidising chemical, to the water to destroy ammonia and nitrogen compounds or swimmer waste. This would be at least five times the normal dose.

SHOTCRETE - Mixture of sand and cement sprayed onto contoured and supported surfaces to build a swimming pool or spa. Plaster is applied over the shotcrete. Shotcrete is premixed and pumped wet to the construction site.

SITE CUT - Also known as ‘Overburden’, the site cut is the removal of excess soil above the pool level that needs to be disposed of before excavation of the swimming pool can begin.

SKIMMER - A box-like device installed through the wall of the pool or spa that is connected to the suction line of the pump that draws water and floating debris in the water flow from the surface without causing much flow restriction, attached to one side/end of the pool used as the main suction point for vacuuming and or skimming of leaves.

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 the 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. The weir also prevents debris from floating back into the pool when the pump shuts off.

SODIUM HYPOCHLORITE - Liquid chlorine, hypochlorite solution, chemical formula NaOCI; usually Provides 10-12% available chlorine; has a pH of 13 and requires that small amounts of acid be Added to the pool to neutralize the high pH.

SOLAR COVER - A cover that, when placed on the water’s surface of a pool, spa or hot-tub, 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 - It is usually panels or coils of plastic or metal through which water passes to increase the temperature from the sun’s radiant heat.

SOLENOID VALVE - An electrical device operated by a magnetic coil to make the valve either open for flow or closed to shut off water flow.

SOURCE WATER - It is the water used to fill the swimming pool or spa (also called ‘tap’ water).

SPOIL - The term used for the soil, dirt and rubble that results from an excavation and is discarded off-site.

STABILISER - Cyanuric Acid is used to screen the pool water from the sun’s UV radiation which attacks the chlorine. The use of this product is recommended for all chlorinated outdoor pools. Regular checking and maintenance during the swimming season is recommended. Stabiliser should not be used in indoor pools.

STEEL FIX - The fastening of steel reinforcing bars so that they stay in the correct place to form the skeletal structure of the swimming pool.

SUPER CHLORINATION - The practice of adding an extra large dose (5 to 10ppm) 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 breakpoint chlorination.

  1. The destruction of compounds such as chloramines
  2. Super sanitising to ensure the destruction of most harmful bacteria; and
  3. A super algaecidal effect to destroy algae spores resistant to normal chlorine levels

SURFACE AREA - The two-dimensional area of an object. The surface area of a swimming pool Is just the length times the width- no depth.

SWIMOUT - A recessed area outside the general perimeter of a swimming pool, also known as an underwater seat. Swimouts are designed to allow ease of entry and exit from the pool.


TELESCOPIC HANDLE - Extension pole made of aluminium used to attach pool accessories.

TEMPORARY FENCING - A safety barrier that is set up during the construction period of the swimming pool. A permanent fence that complies with the Australian Standards must be installed before the swimming pool can be filled with water.

TEST KIT - An apparatus or device used to monitor specific chemical residuals, levels, constituents or demands in the pool or spa water. The kit normally supplied with the pool to enable home testing of the water. Normal levels tested are pH, acid demand, total alkalinity and free available chlorine. Other functions, such as salt and stabiliser levels, calcium
hardness, total dissolved solids and metals in solution can be tested at your Accredited Pool Shop
or service person.

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 colours of the pads compared to a standard set of colours to determine concentration.

THERMOSTAT - A temperature control device that cycles a heater on and off to maintain a desired temperature.

TIME CLOCK - A mechanical or electrical device that automatically controls the periods that a pump, filter, heater, blower, automatic pool cleaner or other electrical devices are on or off.

TOTAL ALKALINITY - Is the measure of bicarbonates, carbonates and hydroxide in the pool water. It is raised through adding sodium bicarbonate, also called “buffer”. As the chemicals used to adjust pH may also affect Total Alkalinity it is recommended that the two be measured together. The chemical reaction between pH and Total Alkalinity may require that they also be adjusted together. Both pH and Total Alkalinity levels should be tested frequently.

TOTAL DISSOLVED SOLIDS - The total amount of dissolved salts, calcium, chlorides and other material in the pool water. This cannot be measured correctly if salt or liquid chlorine is used in the pool.

TOTAL CHLORINE - The combination of free available chlorine and combined chlorine in the pool water.

TOWN PLANNING PERMIT - A Planning Permit is a legal document issued by the local council giving permission to develop or use a piece of land for a specific purpose. A permit may also contain written conditions and endorsed plans showing the proposed development or use of the land. Not all building projects require a Town Planning Permit; examples of planning controls include Heritage or Vegetation Overlays.

TURNOVER - Also called turnover rate. The period of time (usually in hours) required to circulate a volume of water equal to the volume of water contained in the swimming pool or spa. Pool capacity in litres, divided by pump flow rate in litres per minute (lpm), divided by 60 minutes in 1 hour, will give hours for 1 turnover.


UNDERWATER LIGHT - a fixture designed to illuminate a pool or spa from beneath the water’s surface.


VACUUM - This term can be used to define any number of devices that use suction to collect dirt from the bottom and sides of a pool or spa. Most common is a vacuum head with wheels that attaches to a telepole and is connected to the suction line usually via the opening in the skimmer. It must be moved about by a person, and debris is collected in the skimmer basket and filter.

VACUUM HEAD - Attached to the hose and telescopic pole, and used to vacuum dirt from the floor of the pool.

VACUUM PLATE - Designed to sit in the skimmer box above the leaf basket, has a hole in the centre to allow vacuum hose to fit in. Also used for circulating water from the bottom of the pool, in which case a screw-threaded cap is used to block the hole.

VALVE - A mechanical device installed in a water line to close off or regulate the flow of water.

VELOCITY - The speed at which a liquid flows between two points. Usually measured in feet per second.

VENTURI - A fitting or device that consists of a tube constricted in the middle and flared on both ends. A fluid’s velocity will increase and a fluid’s pressure will decrease while passing through the constriction. Placing a tube or pipe at the constriction point creates a vacuum. Fluid or air can be drawn in through the tube. A hydro-therapy jet draws air and mixes it with the water using this principal.

VOLUME - The amount of water a vessel will hold. It is a three-dimensional space occupied by an object. Formula for volume is” Length x Width x Average Depth = cubic metres x 1000 = the volume of the pool in litres.

VORTEX - A revolving mass of water that forms a whirlpool. A funnel-shaped opening is created downward from the water surface.


WATER BALANCE - Water that has a pH of 7.4 to 7.6, a total alkalinity of 80 to 140ppm, calcium hardness of 200 to 400ppm, and a TDS of less than 2500ppm. 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; in-organic salts of aluminium and other metals of water- soluble organic polyelectrolyte.

WATER HAMMER - The shock wave or series of waves produced by the abrupt acceleration or deceleration of water flow through a pipe, caused by inertia. WATERLINE- the height to which the water is filled in the swimming pool and or spa. This is usually in the middle of the skimmer openings, the centre of the tile pattern or to the overflow if so constructed.

WETSEAL - A waterproofing system for protecting internal and external wet areas.

WATERLINE - The height to which the water is filled in a swimming pool and or spa. This is usually in the middle of the skimmer opening.

WET-EDGE POOLS - A wet-edge pool is a swimming pool which produces a visual effect of water extending to the horizon, vanishing, or extending to infinity. Often the water appears to fall into an ocean, lake, river or other similar body of water. Also known as ‘infinity pool’, ‘negative edge pool’ or ‘vanishing edge pool’.