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SWIMMING POOL CHEMICAL AND WATER BALANCE DEFINITIONS:
  • ACID: Liquid (muriatic acid) or dry granular (sodium bisulfate) substance used to lower the pool's pH (toward a more acidic condition) or to lower total alkalinity levels.
  • ACID DEMAND: A titration test used to determine proper amounts of acid (or pH decreaser) to reach correct levels. For example, to lower pH from 8.0 to 7.6, your pool may "demand" 2 qts of acid.
  • ALGAE: Over 20,000 species known to man! Algae may form on your pool surfaces or it may bloom in suspension. We typically know algae to be green, but it may also be yellow (mustard algae), black, blue-green or any shade in between. It may form separate spots, or seem to grow in sheets. Pink algae, is not algae at all, but a form of bacteria. Algae are living, breathing organisms that need warmth, sunlight and CO2 to thrive. For more info: see our algae page
  • ALGAECIDE: Meaning: to kill algae. Algaecides perform best as a backup to a routine sanitation program. They also help to kill airborne spores as they blow into the pool. A variety of algae treatment products are available including copper and silver compounds, poly-quat compounds, chlorine enhancers , and herbicides.
  • ALGAESTAT: An algaecide kills algae, while an algaestat retards and prevents its genesis and growth.
  • ALKALINITY: Alkaline refers to the condition where the water's pH is above 7.0 (neutral) on the pH scale. It is the opposite of acidic. Alkalinity is the amount of carbonates and bicarbonates in the water, measured in ppm of Total Alkalinity.
  • ALUMINUM SULFATE: Also known as alum, this product is used as a flocculant which attracts suspended particles in the water together (green or cloudy pools). Alum sinks everything to the bottom, which is then vacumned to waste. A small amount of alum can also be used as a sand filter additive.
  • BACTERIA: From a health perspective, the most dangerous micro-organisms which may be living in the pool water. Some are pathogens, which can cause infectious diseases.
  • BACTERICIDE: Kills bacteria. Chlorine is a bactericide and germicide. Silver "algaecides" are actually more bactericide, and are useful on pink "algae".
  • BALANCED WATER: Balanced water is the result when all of your chemical parameters are where they should be, and thus "balance" each other. The key components of water balance are pH, Total Alkalinity, Calcium Hardness and Temperature, as measured using the Langelier Index of water balance.
  • BASE: Those chemicals of alkaline nature which will counteract the pH of an acid, eventually neutralizing at 7.0. Common bases used around the pool would include Soda Ash, Sodium Bicarbonate, Sodium Carbonate and Sodium Sesquicarbonate.
  • BASE DEMAND: A titration test used to determine proper amounts of base (pH increaser) to reach correct levels. For example, to raise pH from 7.2 - 7.6, your water may "demand" 2 cups of soda ash.
  • BIGUANIDES: The name for a certain class of sanitizers using the polymer PHMB, the only non-halogen sanitizer available for pool and spa use. Soft Swim and Baquacil are manufacturers of this technology.
  • BREAKPOINT CHLORINATION: When you shock your pool, the goal is to reach a high enough level of free chlorine, measured in ppm, to break apart molecular bonds, specifically the combined chlorine molecules. When breakpoint is reached with sufficient additions of chlorine, everything in the pool is oxidized.
  • BROMAMINES: A combined bromine - ammonia molecule. Unlike chloramines, which are strong smelling and offer no sanitizing properties, bromamine compounds continue to sanitize.
  • BROMINE: A member of the halogen family, commonly used as a sanitizer in spas, because of its resistance to hot water with rapid pH fluctuations.
  • BUFFER: A base such as Sodium Bicarbonate (Baking Soda), added to your pool will increase alkalinity which increases the buffering capacity of the pool; or, your pool's resistance to pH change.
  • BUFFERING CAPACITY: The ability of the pool to resist changes in pH, which prevents water balance. The buffering capacity is given by the alkalinity, a close cousin to pH. If your pH bounces, or resumes previous levels soon after adjustment, your buffering capacity is too low. Check your total alkalinity.
  • CALCIUM CARBONATE: Known as scale, crystalline deposits of calcium may form on your pool surfaces, equipment, or even line your pipes like cholesterol in your arteries. Properly balanced water can prevent this.
  • CALCIUM CHLORIDE: The flaked calcium salt used to raise levels of Calcium Hardness in your pool water. Also good for snow melting.
  • CALCIUM HARDNESS: A titration test is used to determine levels of the mineral calcium dissolved in the pool water.
  • CARBON DIOXIDE: A gas, which when present in the water, provides necessary food for the growth of algae.
  • CARBONATE: Primary in the make up of total alkalinity and TDS.
  • CHITIN: A naturally occurring polymer found in the shells of crabs and lobsters. Contained in the product Sea-Klear, chitin acts as a coagulant and flocculent for oils, metals and organic materials.
  • CHELATOR: A chelating 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. Similar to sequestering agents, chelators are found in such products as Resist and Sea-Klear.
  • CHLORAMINES: The chlorine molecule is strongly attracted to nitrogen and ammonia. When these two hook up, they form a chloramine, which are undesirable, foul smelling, space taking, compounds that require shocking the pool water to get rid of.
  • CHLORINE: A member of the halogen family of sanitizers, it's use in swimming pools is in the elemental form of a gas, or as a liquid, granular or tablet compound. When added to water it acts as an oxidizer, sanitizer, disinfectant and all around biocidal agent.
  • CHLORINE, free available: Free, available chlorine is that which is active, not combined with an ammonia or a nitrogen molecule, and ready to react to destroy organic material.
  • CHLORINE, combined: That 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 available: 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.
  • CHLORINE DEMAND: The quantity of free available chlorine removed during the process of sanitizing. The amount of organic and non organic material contained in the water will "demand" a certain level of oxidizer to be destroyed.
  • CLARIFIER: A clarifier is a chemical used as a coagulant of suspended microparticles. Helps the filter by clumping smaller particles into filterable sizes.
  • COAGULANT: The properties of a chemical used in the assemblage and precipitation of suspended material which may make the pool appear cloudy.
  • CONTAMINANTS: Any microparticle or organism which reduces water clarity or quality or presents health hazards. All of our filtering, circulating and sanitizing is directed here.
  • COPPER: An effective algaestat and algaecide, copper as elemental is used in many pools in products like pooltrine.
  • COPPER SULFATE: Similar to aluminum sulfate, this chemical provides a coagulating and flocculent function in water. Used in ponds. This amount of copper would stain swimming pools.
  • CONDITIONER: Also called Cyanuric Acid (CYA) or stabilizer, this chemical provides a shield from the sun around the chlorine molecule, extending the efficacy...aka; saving you money.
  • CORROSION: The effects of a 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.
  • 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 sanitizing ability.
  • DISINFECTANT: Chemicals or processes which work to destroy vegetative forms of microorganisms and other contaminants. Examples are chlorine, bromine, Soft-Swim, ionizers and copper and silver algaecides.
  • DIRECTIONS: What you should read before using any chemicals.
  • DIRT DEMAND: The demand that your pool has for dirt. This level is invertedly proportional to available time for cleaning. If you remove the dirt from the pool, you have created a dirt deficit, and the pool will actually suck dirt out of the air to maintain its dirt demand.
  • DPD: A method of testing for chlorine levels in the pool water. Unlike OTO, DPD testing allows determination of total and free available chlorine levels, which, through subtraction, gives us combined levels.
  • DRY ACID: Sodium bisulfate, a granular form of acid , used to lower pH and alkalinity in the water. Safer and less caustic than muriatic acid. Usually available as a "pH decreaser."
  • EFFICACY: The power to produce an effect. Chlorine's efficacy is affected by many factors, including the sun, water balance and the water's chlorine demand.
  • ENZYMES: Used in swimming pool formulations designed to break down and digest oils in a pool or spa similar to the way enzymes are used in oil spill clean-up efforts.
  • FILL WATER: Used in filling or adding to the water level. Whether from the hose or from a well, your fill water brings its own chemical make up and water balance (or lack thereof).
  • FILM-X: A compound of citric acid used in cleaning plaster and other pool areas. Safe replacement for muriatic acid.
  • FOAMING: A term used to describe surface foam on your water, esp in spas/hot tubs. Foaming is caused by high TDS levels working in combination with soft water and oils. Certain low grade algaecides can foam when added to pool or spa. Use enzymes for foam control.
  • FLOCCULANT: Essentially the same as a coagulant, this chemical (such as alum) is used to combined suspended alkaline material and-or algae into a heavy gel, which sinks to the bottom for vacumning.
  • HALOGEN: A member of the family of elements fluorine, bromine, chlorine and iodine.
  • HARD WATER: That water which is high in calcium hardness and other salts which, as such, resists soap being lathered.
  • HYPOCHLORITE: A family of chlorine compounds such as Calcium Hypochlorite and Lithium Hypochlorite, both granular, and the liquid Sodium Hypochlorite. When these compounds contact water, they release Hypochlorous Acid, the active sanitizing agent.
  • IONIZER: An ionizer is a device mounted on your return line, and through which water flowing will receive charged metal ions. Manufacturers may use a copper anode and/or silver. Copper is an algaecide and algaestat, while silver is known for its properties as a bactericide. This electric, limited technology has been replaced by the Vision System.
  • IRON: Usually introduced into the water from iron plumbing or from well water, Ferric Iron can stain surfaces, while Ferrous Iron will turn your water a clear green color.
  • LANGELIER INDEX: Also called the Saturation Index, Mr. Langelier devised a system to determine water balance by assigning values to levels of pH, Total Alkalinity, Calcium Hardness and water Temperature. When all parameters are in balance, the water will neither be corrosive or scaling.
  • MINERALS: Such as Calcium, Manganese, Magnesium, Nickel, Copper, Silver, Iron, Cobalt or Aluminum. Their presence in high non-chelated concentrations can lead to stains & scale when conditions are right.
  • MICROORGANISM: A living, breathing creature in your pool. The purpose of disinfectants are to remove such "infectants".
  • MURIATIC ACID: The liquid dilution of Hydrochloric Acid used to lower pH and alkalinity, and to remove mineral stains and scale. Extremely caustic and corrosive.
  • NASCENT OXYGEN: A single oxygen atom, not yet bonded to anything. Extremely powerful oxidizer when harnessed.
  • 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 tonics, etc.) or be introduced by other means.
  • NON-CHLORINE SHOCK: A granular form of potassium permonosulfate, used to oxidize materials such as microorganisms, contaminants or chloramines.
  • OTO: Another method of testing for free available chlorine levels in your pool, as in an OTO test kit.
  • OXIDATION: The "burning up" of organic waste and compounds in the pool water. It also refers to what you may see on your metal pool surfaces if your water is corrosive. Rust is a form of this kind of oxidation.
  • OZONE: The molecule containing three atoms of oxygen; known to be a very powerful sanitizer. Ozone producing equipment creates this molecule by UV radiation or corona discharge generators.
  • pH: The scale of relative acidity or alkalinity, expressed in logarithmic numbers from 0 - 14, with 7.0 being neutral. What's really being measured is the hydrogen ion concentration. Some would say pH stands for Power of Hydrogen.
  • POTASSIUM PERMONOSULFATE: See non-chlorine shock.
  • POLYMER: An algaecide-algaestat made up of repeating polymer molecules. Used for green algae and available in varying strengths.
  • 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 parts per million, by weight and in relation to the water it's dissolved in.
  • PRECIPITATION: To precipitate is to come out of solution; become insoluble by result of chemical action. Material forced out of solution, purposefully or accidentally, will then settle, stain or scale, or remain suspended in the water.
  • QUATERNARY AMMONIUM COMPOUND: A type of algaecide composed of ammonia compounds. Effective algaestat for green and blue/green algae.
  • REAGENT: The chemical indicators used in testing water balance. (All the little bottles or tablets in your test kit).
  • RESIDUAL: Usually refers to free available chlorine levels remaining in the pool after initial treatment or activity with contaminants.
  • SANITIZER: A chemical agent used to remove unwanted contaminants.
  • SCALE: Usually whitish in color, 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.
  • SEQUESTERING AGENT: Like when OJ's jury was sequestered? A sequestering agent ties-up minerals tightly in solution, preventing their precipitation, which colors the water and/or stains the pool. Synonymous to chelators, these are commonly called stain & scale chemicals.
  • SHOCK: As a noun it loosely describes the products used in shocking, such as hypochlorites, potassium permonysulfate or hydrogen peroxide. As a verb it describes the act of bringing the sanitizer level up so high that breakpoint chlorination is reached. When breakpoint is reached, a "shock" or perhaps a "lightning bolt" is a better analogy, is sent through the water, tearing apart molecules and slashing through cell walls. Ultimate purification, man.
  • SODA ASH: A base, used to counteract an acidic condition by raising pH.
  • SODIUM BICARBONATE (baking soda): Another base, however its properties will increase alkalinity more than pH. Used to raise Total Alkalinity levels.
  • SODIUM BISULFATE: An granular form of acid, used to counteract a scaling condition by lowering pH and/or alkalinity.
  • SODIUM HYPOCHLORITE: Liquid chlorine used in pools, identical yet stronger than Clorox bleach.
  • SODIUM TETRABORATE: New technology that renders algae incapable of processing carbon dioxide, which they need to live.
  • SODIUM DICHLOR: A granular form of chlorine that is stabilized with cyanuric acid. Used for shocking and superchlorination.
  • SOFT WATER: Water that has low calcium and/or magnesium content. Soap lathers easily in soft water.
  • STABILIZER: See Cyanuric Acid. Stabilizers, also called conditioners, can be added directly to your pool to extend your chlorine efficacy. Cyanuric acid is already added to certain "stabilized" products such as Trichlor tablets and Sodium Dichlor.
  • SUPERCHLORINATION: Applying 7 - 10 times the normal amounts of chlorine to the pool as an added "boost" for contaminant removal. Some refer to superchlorinating as being less than shocking, in that breakpoint thresholds are not reached, or the terms may be used synonomously.
  • TITRATION: A method of testing for total alkalinity, calcium hardness and acid/base demand by adding a titrant, drop by drop until a color change is observed.
  • TOTAL ALKALINITY: The ability of the pool water to resist changes in pH. The "buffering" capacity of the water. Additions of Sodium Bicarbonate will increase the levels, expressed in ppm.
  • TOTAL DISSOLVED SOLIDS (TDS): A measure of everything that has ever dissolved in the water; all the matter that is in solution. High TDS levels can oversaturate your water, causing all sorts of reactions.
  • TURBIDITY: Cloudy, dull, hazy water, due to microparticle suspension.
  • ULTRA VIOLET LIGHT TREATMENT: Using UV wavelength radiation to destroy contaminants in water. UV light is also used to create ozone molecules for the same purpose.
  • VISION SYSTEM: The technology which isolates nascent oxygen into a powerful sanitizing tool. See Cationic Sanitation.

POOL STRUCTURE AND SWIMMING POOL EQUIPMENT:
  • AIR BLEEDER ASSEMBLY: Located on the top of the filter, sometimes accompanied by a pressure gauge, the bleeder is opened to release air trapped in the filter.
  • AUTOMATIC POOL CLEANER: A device which agitates or vacumn debris from the walls and floor of the pool.
  • BACKFILL: The repositioning of the soil after construction of a pool.
  • BACKWASH: The process of thoroughly cleaning the filter medium and/or elements by reversing the flow of water through the filter to waste.
  • BALL VALVE: A device with a hollowed out ball inside which can be turned with an external handle to decrease or increase flow.
  • BLOWER: Plumbed into the spa return line, air is injected to produce fun bubbles and a hydrotherapy effect in the spa.
  • BOOSTER PUMP: Secondary to the filter pump, a booster pump is used to power an automatic pool cleaner such as Polaris or Letro.
  • BTU: British Thermal Unit. A unit of measurement for the use of gas by a gas appliance. Pool heaters are rated by their consumption.
  • CAPACITY: The gallonage of the pool. Want the formula?
  • CARTRIDGE: One type of filtration, the cartridge is a pleated, porous element through which water is passed through.
  • CHECK VALVE: A one way flow device.
  • CHLORINATOR: Devices which allow for the safe, controlled introduction of chlorine into the water.
  • CHLORINE GENERATOR: A miniature chlorine factory, this device creates its own sanitizer for your pool.
  • CIRCUIT BREAKER: A switch which allows manual override of an electrical circuit. It also automatically breaks the circuit when current fluctuations are detected.
  • CIRCULATION SYSTEM: The "circuit" of plumbing which continuously carries the water out of the pool, through the pump & filter, and returns it to the pool.
  • CONDUIT: A pipe, usually gray pvc or flexible pvc designed to carry wires from a source (i.e. time clock) to a load (i.e. pump motor).
  • COPING: The capstone on top of the bond beam which finishes the edge around a pool or spa. It may be precast concrete or brick. On vinyl liner pools pre fab coping is usually part of an integrated system for the wall, vinyl liner and deck.
  • COUPLING: A plumbing fitting designed to join two pieces of pipe.
  • COVERS: Automatic covers: Solid, reinforced vinyl which rolls onto a reel on one end of the pool and attaches on the sides into small aluminum tracks. Can be motorized or hand crank. Some models may snap the sides into small anchors placed into the deck, providing more shape flexibility. Provides safety (with water pumped off), debris protection and heat/chemical/water retention. Hard Covers: A cover which rests on the edge or coping of the spa or small pool. Provides a barrier to debris and possibly people, while keeping the heat trapped in. Solar Covers: Sometimes called a thermal blanket, this cover floats on the surface, magnifying the sun's rays to warm the water and also provide chemical/heat/water evaporation. Winter Covers: A barrier to sun and debris, winter covers secure the pool from contamination. These are subdivided below. Mesh Covers: These stretch tightly across the pool like a trampoline. The only covers which can be called safety covers in that the mesh polypropylene allows precipitation to pass through. Solid Covers: These are usually made of some form of plastic or vinyl and are secured around the edges either by aqua bloks or similar weight or the edges attach to anchors set in the concrete or wood deck.
  • DIATOMACEOUS EARTH: The filtering medium of the DE filter, this dry powder is the fossilized remains of the ancient plankton, diatom.
  • DIATOMACEOUS EARTH FILTER: A filter tank containing fabric covered grids which hold the DE powder up against the flow of the water.
  • DIVERTER VALVE: Used in a twin port skimmer, a diverter allows the operator to manipulate the amount of flow from the main drain and skimmer to the pump.
  • 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 center bottom of the pool.
  • EFFLUENT: The water that flows out of the pump, on its way through the filter, heating and treating equipment, and returning to the pool. Also known as the pressure side.
  • ELBOW: A 90 or 45 degree plumbing fitting. Used where your pipes take a turn.
  • FILTER: A device used to remove particles suspended in the water by pumping water through a porous substance or material.
  • FILTER ELEMENT: A device inside a filter tank designed to entrap solids and direct water through a manifold system to exit the filter.
  • Cartridge filter elements and DE filter grids are two examples.
  • FILTER MEDIUM: A finely graded material, such as sand, diatomaceous earth, polyester fabric or anthracite coal that removes suspended particles from water passing through it.
  • FILTER 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 (gpm).
  • GATE VALVE: The type that spins "lefty-loosey; righty-tighty".
  • GAS VALVE: An electronic valve in the pool heater that directs gas flow from the meter to the pilot and the burner tray.
  • GROUND-FAULT CIRCUIT-INTERRUPTER: A GFCI device protects a circuit from branching off by de-energizing the path of electricity very quickly when it senses current loss. An important safety device around water (the pool?).
  • GUNITE: A dry mixture of cement and sand mixed with water at the "gun"; hence the name. A gunite operator "shoots" the pool's rough shape, while finishers trowel after.
  • HEATER: A device used to heat the water. It may be electric, fuel operated or solar powered heat.
  • HEAT EXCHANGER: A set of 8 or 10 ribbed copper tubes that absorb the heat produced below it and transfer it to the water cycling through its tubes.
  • HEAT PUMP: The antithesis of the air conditioner, the heat pump's cooling coil removes heat from the air while the condenser coil transfers it to water cycling through it.
  • HOT TUB: Usually considered a circular, wooden vessel filled with heated and circulated water.
  • HYDROSTATIC PRESSURE: A force involving built up ground water which creates upward pressure beneath the pool shell.
  • HYDROSTATIC RELIEF VALVE: Fitting(s) installed in the floor of the pool designed to manually or automatically release hydrostatic pressure beneath the pool by allowing ground water into the pool.
  • IMPELLER: The rotating vanes of a centrifugal pump; its action creates the flow of water. The impeller is shaft driven by an electric motor.
  • INFLUENT: The water coming into and up to the impeller from the suction lines. These pipes are under vacumn pressure.
  • JANDY VALVE: A brand name of a three way valve, which has simplified pool plumbing.
  • JET PUMP: Used in spas to provide additional thrust into the hydrotherapy jets.
  • LADDER BUMPERS: Rubber caps or inserts which protect the pool plaster or vinyl liner from the sharp steel ends of the ladder.
  • 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.
  • LOAD: An electric device which consumes energy, placing a load on the source.
  • LOW WATER SUCTION: An influent fitting, typically low on the wall in the deep end of a vinyl liner pool. A cheaper alternative to a main drain.
  • MECHANICAL SEAL: A seal behind the impeller which prevents water from running out along the shaft of a motor. aka; pump seal.
  • MOTOR: A machine for converting electrical energy into mechanical energy. Your motor is known as the dry end of the filter pump. It drives the impeller, which moves the water.
  • MULTIPORT VALVE: A 4 or 6 position valve combining the functionality of several valves into one unit, revolutionizing pool plumbing. The six common functions are described below:

    Filter: This is normal water flow through the filter, say, top to bottom. This is where the valve sits 99% of the time. Backwash: When the pressure gauge indicates, you will need to backwash the filter. When the handle is turned to backwash, the flow through the filter is reversed, say, bottom to top. The effluent water (out of the filter) is directed to the waste line. Rinse: After backwashing, it's a good idea to rinse for 15-20 seconds to remove any residual dirt that may "poof!" back into your pool after backwashing. Rinse flows through the water in filter fashion, say, top to bottom, but effluent is sent out the waste line.

    Recirculate: This setting bypasses the filter, water coming into the multiport does a U-turn and heads back towards the pool. Used only when the filter is broken (at least it's circulating), or when adding specialty chemicals which specify using this setting. Drain / Vacumn to waste: This useful setting allows you to vacumn up large volumes of debris that would either clog the filter or pass through it because of its small size. Dirt that is vacumned passes right out the waste line. It is also the setting of choice when draining the pool or lowering the water level (if you didn't need to backwash, which also lowers the water level).
  • PLASTER: A common type of interior finish applied over the concrete shell of an inground swimming pool.
  • PRESSURE CHECK: A test for the rate of water flow; also a test for leaks in plumbing by placing a line in question under pressure and waiting for the pressure to drop.
  • 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 impeller towards the pool.
  • PRESSURE SWITCH: A switch used in pool heaters which opens when the flow rate is insufficient for safe heater operation. This disrupts the circuit in the heater, preventing it from firing.
  • PLUNGER: The sliding disc assembly that changes valve position in a push-pull valve. For example; up for backwash, down for filtration.
  • PUSH-PULL VALVE: A two position valve used for backwashing sand or DE filters.
  • PUMP: A mechanical wet-end, powered by an electric motor, which causes hydraulic flow and pressure for the circulation of the pool water.
  • PVC: Polyvinyl chloride, which is used to make flexible and rigid PVC pipe used for pool plumbing.
  • RATE OF FLOW: Quantity of water flowing past a designated point within a specified time period, measured in gallons per minute (gpm).
  • RESTRICTED FLOW: The term used to describe a condition preventing full flow of water. Restriction can occur with full skimmer or strainer baskets, obstructions in the plumbing, dirty filter, undersized plumbing or equipment , or placing devices like, heaters, cleaners or fountains in the circulation system. Restriction on the suction side creates higher vacumn, (or suction) while on the pressure side creates higher pressure.
  • RE-BAR: Reinforcement bar, used to add strength to a concrete. After excavation of an in ground pool, a steel cage is formed out of re-bar, and the gunite shell is shot over and surrounding it.
  • SAND FILTER: A filter tank, usually fiberglass 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 on the bottom.
  • SHOTCRETE: A different type of application of the concrete and sand mix which is used to "shoot the shell". Gunite is pumped dry and mixed with water at the gun, whereas shotcrete is pumped wet.
  • SKIMMER: A surface skimmer is a plumbing fitting set at water level, containing a weir mechanism and a debris basket. The skimmer is part of the suction side circulation system.
  • SKIMMER BASKET: Beneath the lid, the basket strains debris, as the first line of defense in filtering the water.
  • SKIMMER NET: Attached to a telescopic pole, a leaf rake is a very useful tool in keeping the pool clean. Also called a skimmer net are the flat, "dip and flip" nets, which aren't so useful.
  • STRAINER BASKET: The second line of defense is a basket at the pump. The holes in this are smaller than those in a skimmer basket, and prevent the pump impeller from clogging up.
  • SOLAR SYSTEM: Black mats of miniature plastic tubes through which water is pumped, absorbing the heat as it passes through. These mats are roof mounted with up & down plumbing connecting it.
  • SOURCE: Refers to the origination of electrical power. The source for your filter pump (load) is probably a timer clock.
  • SUCTION SIDE: The plumbing prior to and carrying water to the pump. This side is under vacumn pressure.
  • SPA: A filtered, hot water vessel with hydrotherapy jets and air induction. Can be portable or installed permanently. Jacuzzi is a brand name.
  • TEE: A plumbing fitting used to bring two pipes together into one, or vice-versa.
  • TEST KIT: What you should be using more frequently to determine the water balance in your pool.
  • TIME CLOCK: A mechanical device that controls the timed operation of your electrical equipment, primarily your filter and booster pumps.
  • 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.
  • UNDERDRAIN: The lower collection system in a filter which directs filtered water back towards the pool. It also distributes water in reverse during backwashing. See laterals.
  • VACUUM: Refers to the low pressure condition created in the suction line. Also refers to the cleaning process of sucking leaves, algae and debris from the pool floor.
  • VALVES: A device placed in the plumbing line which restricts or obstructs water flow to create desired hydraulics, or may permit flow in one direction only (as in a check valve).
  • VENTURI: Increasing water velocity by restricting pipe size.
  • VINYL LINER: One type of interior finish. The liner is draped over a sand or cementitious floor, and locked into the top of the wall.
  • WEIR: The device in a skimmer that controls the amount of water coming into the skimmer, and keeps debris inside. That "flapper-gate thing".