SWIMMING POOL GLOSSARY

A
ACID: Liquid (Muriatic Acid) or Dry Granular (Sodium Bisulphate) substance is used to lower the swimming pools pH or to lower Total Alkalinity levels.

AIR RELIEF VALVE/AIR BLEED ASSEMBLY: A manually operated brass or plastic valve located at the top of a filter tank for relieving the pressure inside the filter and removing air inside the filter (bleeding the filter). Also known as a pressure relief valve.

ALGAE: Microscopic plant-like organisms that contain chlorophyll. Algae is nourished by carbon dioxide CO2) and use sunlight to carry out photosynthesis. It can be introduced by rain or wind and grows in colonies, producing nuisance masses. Algae can harbour bacteria and can be slippery. There are thousands of known species of algae. The most common type of algae found in pools are black, blue-green, green and mustard (yellow or drawn). Click here to learn more about algae.

ALGAECIDES: Chemical compounds designed to kill, prevent and control algae. Algaecides perform best as a backup to a routine sanitation programme. They also help to kill airborne spores as they blow into the pool. A variety of treatment products are available.

ALKALINITY: Alkalinity is the measure of alkaline salts relevant to water balancing. It is the opposite of acidic. Alkalinity is the amount of carbonates and bicarbonates in the water, measured in ppm (parts per million) of Total Alkalinity.

ALUMINIUM SULPHATE: This product is used as a flocculent which attracts suspended particles in the water together (green or cloudy pools). Aluminium, or ‘Alum’ as it can be known, sinks everything to the bottom of the pool which is then vacuumed to waste.

AUTOMATIC POOL CLEANER: A pool maintenance system that will agitate and/or vacuum debris from the pool interior automatically.

B
BACKFILL: The re-positioning of the soil after construction of a pool.

BACKWASH:  The process off thoroughly cleaning the filter by reversing the flow of water through the filter to waste.

BACTERIA: Micro-organisms which may be living in the pool water. Some are pathogens, which can cause infectious diseases.

BALANCED WATER: Chemical compound designed to prevent corrosion and staining by balancing the pH, total alkalinity and calcium hardness in pool water. Balanced water is the result when all your chemical parameters are where they should be, and thus balance each other.

BALL VALVE: A device with a hollowed out ball inside, which can be turned with an external handle to decrease or increase the flow.

BLOWERS: Plumbed into the spa return line, air is injected to produce fun bubbles and a hydrotherapy effect in a spa.

BOOSTER PUMP: Secondary to the filter pump, a booster pump is used to power an automatic pool cleaner such as the Polaris.

BROMINE: A member of the halogen family, commonly used as a sanitiser in spas. Available as a tablet or as sodium bromide, a granular salt.

BTU: British Thermal Unit. A unit of measurement for the use of gas by a gas appliance. The amount of heat necessary to raise 1lb. of water by 1 degree of Fahrenheit.

C
CALCIUM: Calcium is a sift grey alkaline earth metal.

CAPACITY: The total number of gallons of pool water your pool contains (gallons).

CAPACITOR: The capacitor is the battery for your pool motor. It provides the energy needed while starting, to reach 2450 rpm quickly.

CARBON DIOXIDE: A gas which when present in the water, provides necessary food for the growth of algae.

CARTRIDGE: One type of filtration, the cartridge is a pleated, porous element through which water is passed through.

CENTRIFUGAL PUMP: A pump consisting of an impellor fixed on a rotating shaft and enclosed in a casing or volute and having an inlet and a discharge connection. The rotating impellor creates pressure in the water by the velocity derived from the centrifugal force.

CHEMICAL FEEDER: A device that dispenses chemicals into the pool or spa water at a predetermined rate. Some dispense chlorine or bromine while others dispense pH-adjusting chemicals.

CHLORAMINES: The chlorine molecule is strongly attracted to nitrogen and ammonia. When these two combine they form a chloramine, which are undesirable, foul smelling, space taking compounds that require shocking the pool water to get rid of.

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 and control bacteria and algae. In addition chlorine oxidises ammonia and nitrogen compounds caused by swimmers.

CHLORINE – FREE: Free available chlorine is that which is active, not combined with ammonia or a nitrogen molecule, and react to destroy organic material.

CHLORINE – COMBINED: The portion of total available chlorine left over when free available is subtracted. The measure of chlorine which has already attached itself to other molecules or organisms. Most of this is made up of chloramines.

CHLORINE – TOTAL: The sum of combined and free chlorine levels. With a DPD test kit, one determines free available level, then total available. The difference, if any is the level of combined chlorine.

CIRCULATION SYSTEM: The circuit of plumbing which continuously carries the water out of the pool, through the pump and filter then returns it to the pool.

CLARIFIER: A clarifier is a chemical used as a coagulant for suspended micro particles. It helps the filter by clumping the smaller particles into filterable sizes.

COAGULANT: A product used to gather together the small suspended particles in the pool water which make it appear cloudy.

CONDUIT: A pipe, usually pvc or flexible designed to carry wires from a source (i.e. time clock) to a load (i.e. pump).

COPING: The cap or top lip on the pool or spa wall that provides a finished edge around the pool or spa. It may be pre-cast concrete or brick. On vinyl liner pools pre-fabricated coping is usually part of an integrated system for the wall, vinyl liner and deck.

COPPER: An effective algaecide.

CORROSION: The etching, pitting and eating away of the pool or spa equipment. Can be caused by improper water balance, misuse of acid or acidic products or from soft water.

COUPLING: A plumbing fitting designed to join two pieces of pipe.

COVER – AUTOMATIC: Solid reinforced vinyl which rolls on a reel on one end of the pool and attaches on the sides into a small aluminium tracks. It can be motorised or hand-crank style. Some models may snap the sides into small anchors placed into the deck providing more shape flexibility. Provides (with water pumped off – cover pump), debris protection, and heat/chemical/water retention.

COVER – SOLAR: 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 windborne debris from entering the water.

COVER – WINTER/DEBRIS: A barrier to sun and debris. These usually stretch tightly across the pool like a trampoline; they allow precipitation to pass through.

CYANURIC ACID: A granular chemical added to the pool water which provides a shield to chlorine for protection from UV radiation, which disrupts the molecule, destroying its sanitising ability.

D
DIATOMACEOUS EARTH (DE): A porous substance used in certain types of pool filters. A dry powder made from the fossilised remains of ancient plankton.

DISINFECTANT: Chemicals or processes which work to destroy vegetative forms of micro-organisms and other contaminants i.e. chlorine, bromine, ionisers.

DIVERTER VALVE: A plumbing fitting used to change the direction or redirect the flow of water. Some diverter valves are used on pool/spa combinations to allow the use of the spa and then switch the flow back to the pool.

DPD: A method of testing for chlorine levels in the pool water. DPD testing allows determination of total and free available chlorine levels which through subtraction gives us combined levels.

DRAIN: Also called the “main drain”, this plumbing fitting is the start of one suction line to the pump and is usually situated at or near the centre bottom of the pool.

DRY ACID: Sodium bisulphate, a granular form of acid used to lower the pH and alkalinity in the water. It is safer and less caustic than muriatic acid.

E
EFFICACY: The power to produce and effect. Chlorine efficacy is affected by many factors, including sun and water balance.

F
FILTER: A device used to remove particles suspended in the water by pumping water through a porous substance or material.

FILTER MEDIA: A finely graded material such as sand or diatomaceous earth that removes suspended particles from water passing through it.

FILER PUMP: The device that pulls water from the pool and pushes it through the filter on its way back to the pool.

FILTRATION RATE: The rate of water pumped through a filter, in gallons per minute.

FLOCCULENT: Essentially the same as a coagulant, this chemical is used to combine suspended alkaline material and/or algae into a heavy gel, which sinks to the bottom of the pool for vacuuming.

FLOW RATE: The quantity of water flowing past a designated point within a specific time, such as the number of gallons flowing past in 1 minute.

H
HALOGEN: a member of the family of elements fluorine, bromine, chlorine and iodine.

HARD WATER: The water which is high in calcium hardness and other salts which, as a result, resists soap being lathered.

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

I
IMPELLOR: The rotating vanes of a centrifugal pump. Its action creates the flow of water. The impellor is shaft driven by an electric motor.

ION: An atom, or group of atoms that possess an electrical charge.

IONISER: An Ioniser us a device mounted on your return pipe line and through which water flowing will receive charged metal ions. Manufacturers may use a copper and silver anode. Copper is an algaecide and silver is known for its bacteriological properties.

L
LATERALS: Elongated, capped plastic nipples at the bottom of a sand filter which are slotted to allow for water passage while keeping the sand in the filter tank.

LINER: Also called a vinyl liner. The vinyl membrane acts as the container to hold or contain the water in some types of pools.

LANGLIER INDEX: Also called the Saturation Index. Mr Langlier devised a system to determine water balance by assigning values to levels of pH, total alkalinity, calcium hardness and water temperature. When al parameters are in balance the water will neither be corrosive or scaling.

M
MECHANICAL SEAL: A seal behind the impellor which prevents water from running out along the shaft of a motor

MICROORGANISMS: Living, breathing creatures in the pool. The purposes of disinfectants are to remove such infectants.

MULTIPORT VALVE: A 4 to 6 position valve combining the functionality of several valves into one unit, revolutionising pool plumbing. The six common functions are described below:
                  FILTER: Keep it here 99%, except when backwashing, rinsing or wasting.
                  RINSE: Use this setting for 20 seconds after backwashing to rinse tank.
                  RE-CIRCULATE: Use this if the filters broken, at least you’re circulating.
                  BACKWASH: Use this setting to reverse the flow in the filter and send water
                 out of the waste line. Make sure valves are open or hoses rolled out.
                  WASTE/DRAIN: Another filter bypass setting, but this setting sends the water out                  of the waste pipe (hose), instead of returning it to the pool. This setting is used to
                 lower pool water level or to vacuum to waste.

N
NITROGEN: When combined with chlorine, nitrogen creates chloramines, which do not belong in our pool. Nitrogen can be found in many swimmer wastes (perspiration, suntan oil, hair lotions etc.) or is introduced by other means.

NON-CHLORINE SHOCK: A granular form of potassium permonosulphate , used to oxidise materials such as micro-organisms, contaminants and chloramines.

O
O-RING: A loop of elastomer with a round (o-shaped) cross-section used as mechanical seal or gasket. They are designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.

OXIDISER: A non-chlorine shocking compound that removes or destroys built-up contaminants and chloramines in pool water without raising chlorine levels.

OZONE: The molecule containing three atoms of oxygen, known to be a very powerful sanitiser. Ozone producing equipment creates this molecule by UV radiation or corona discharge generators.

P
pH: The scale of relative acidity or alkalinity, expressed in logarithmic numbers from 0 – 14, with 7.0 neutral. What’s really being measured is the hydrogen ion concentration. Some would say pH stands for Power of Hydrogen.

PPM: Parts per million. A method of assigning value to certain concentrations of chemicals in the water. For example, alkalinity should be kept at 80-120 part per million, by weight and in relation to the water it’s dissolved in.

PRESSURE GAUGE: A device indicating pressure in a filter system, Provides a determination of how the system is operating, and informs us when service is required.

PRESSURE SIDE: The return side of the plumbing, The section from the pump impellor towards the pool.

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 hot tubs.

PUMP STRAINER BASKET: A device placed on the suction side of the pump, which contains a removable strainer basket designed to trap large debris in the water flow without causing restriction. Sometimes called a pump leaf trap.

R
RESIDUAL: Usually refers to free available chlorine levels remaining in the pool after initial treatment or activity with contaminants.

S
SAND FILTER: A filter tank, usually fibreglass or ABS plastic filled with sand and gravel. The pump diffuses water over the top of the sand bed, and forces it through the sand and into the laterals in the bottom.

SANITISER: A chemical agent used to remove unwanted contaminants.

SCALE: Usually whitish in colour, scale forms on pool surfaces and equipment when mineral salts are forced out of solution. A scaling condition is one in which calcium hardness; pH and/or alkalinity levels are out of balance.

SHOCK TREATMENT: The practice of adding significant amounts of an oxidising chemical to the water to destroy ammonia and nitrogen compounds caused by swimmers, the environment and/or weather.

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 the water flow from the surface without causing flow restriction.

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 on the water flow from the surface without causing flow restriction.

SKIMMER NET: Attached to telescopic pole, a leaf rake is a very useful tool in keeping the pool clean.

SODA ASH: A base, used to counteract and acidic condition by raising pH.

SODIUM BICARBONATE: Another base, used specifically for raising alkalinity levels.

SODIUM HYPOCHLORITE: Liquid chlorine used in pools.

SOFT WATER: Water that has a low calcium and/or magnesium content. Soap lathers easily in soft water.

STABILISER: See cyanuric acid.

STRAINER BASKET: The second line of defence is a basket in the pump. The holes in this are smaller than those in the skimmer basket, and prevent the pump impellor from clogging up.

SUCTION SIDE: The plumbing prior to and carrying water to the pump. This side is under vacuum pressure.

SUPER-CHLORINATION: Applying 7-10 times the normal amount of chlorine to the pool as an added boost for contaminant removal.

T
TDS: See total dissolved solids.

TEST KIT: An apparatus or device used to monitor specific chemical residuals, levels, constituents or demands in pool or spa water. 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 or spa water. The strips are usually dipped in the water, and the resulting colours of the pads are compared to a standard set of colours to determine concentration.

TOTAL DISSOLVED SOLIDS: A measure of everything that has ever dissolved in the water, all matter in solution. High TDS levels can oversaturate your water causing all sorts of reactions.

TURBIDITY: The cloudy condition of the water due to the presence of extremely fine particles in suspension that cannot be trapped by the filter because they are too small. Adding a clarifier, will coagulate the particles and make the filter more efficient.

TURNOVER: The amount of time it takes your pump to move all the water in your pool through the filter and back again. Usually pools are designed for an eight hour turnover.

U
ULTRA VIOLET LIGHT (UV): Ultra violet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than soft x-rays. It is so named because the spectrum starts with wavelengths slightly shorter than the wavelengths humans identify as the colour violet (purple).

V
VACUUM: 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 telescopic pole and is connected to the suction line, usually via the opening in the skimmer. Pool vacuums must be operated by a person and debris is collected in the filter.

VALVES: A device placed in plumbing line which restricts or obstructs water flow to create desired hydraulics, or may  permit the flow in one direction only (as in a check valve).

VOLUTE: A volute is a curved funnel increasing in area to the discharge port. It is often used with impeller pumps. As the area of the cross section increases, the volute reduces the speed of the liquid and increases the pressure of the liquid. One of the main purposes of a volute casing is to help balance the hydraulic pressure on the shaft of the pump. However, this occurs best at the manufacturers recommended capacity. Running volute-style pumps at a lower capacity than the manufacturer recommends can put lateral stress on shaft of the pump, increasing wear-and-tear on the seals and bearings and on the shaft itself.

VINYL LINER: The vinyl membrane that acts as the container to hold or contain pool water. The liner is draped over sand or cement floor and locked into the top of the pools wall.

W
WATER CLARIFIER: Also called a coagulant or flocculent. A chemical compound used to gather or to precipitate suspended particles so they may be removed by vacuuming or filtration.

WEIR: The small floating door on the side of the skimmer that faces the water over which water flows on its way to the skimmer. Adjusts automatically to small changes in water level to assure a continuous flow of water to the skimmer. The weir also prevents debris from floating back into the pool after the pump shuts off. Also known as the skimmer weir.