Pool Terminology
Whether you are considering building a new pool, you are in the process of a build or you are a pool owner, this page of key industry terms will help you better understand some of the language that is spoken in the pool world!
Acid: A liquid or dry chemical used to lower the pH and/or alkalinity of pool or spa water.
Acid Wash: A procedure using an acid solution to clean an interior surface of a pool with subsequent neutralization of the acid.
Aggregate: Marble dust, sand, rocks, pebbles, colored quartz, dolomite and other similar materials used as components of concrete or plaster.
Air Blower: A device that produces a continuous flow of air.
Algae:Minute plant life growing in water in the presence of sunlight and carbon dioxide.
Anti-vortex Drain Cover: A plate or cover that is affixed to the main outlet of a swimming pool or spa that prevents a vortex from forming as water passes through to the main outlet.
Backfilling:Filling space between pool shell and sides of excavation with dirt.
Back Pressure:Resistance to flow, normally expressed in pounds per square inch (kilograms per square centimeter)
Backwash:Process of running water through a filter opposite the normal direction of flow to flush out contaminants.
Balance:The term in water chemistry to indicate that when measuring all components together, the water is neither scaling nor corrosive.
Ball Valve:A device utilizing a ball-shaped diverter to partially or totally obstruct the flow of water.
Barrier: A means to limit, delay, or restrict access to a pool, spa, or hot tub.
Bleeder Valve: A device that allows air to be vented from a system.
Blister: An area of raised surface detached from the structural matrix of a material.
Blower: An electromechanical device that generates air pressure to provide spa jets and rings with bubbles.
Bond Beam: Reinforced masonry units designed to resist horizontal forces.
Bonding (electrical): The joining of metallic parts to form an electrically conductive path, which will ensure electrical continuity.
Booster Pump System: A pump that is completely independent of the filtration and heating system. Used to provide support for hydrotherapy jets, cleaning systems and gas chlorinators or special water features.
Break in Grade: Occurs when the slope of the pool floor changes to a greater slope.
Brown Coat: A coat of plaster applied with a fairly rough texture to receive the finish coat.
BTU: British Thermal Unit. A unit of measurement used to define the capabilities of heaters. One BTU is capable of raising the temperature of one pound of water by one degree Fahrenheit.
Bull Nose: A brick or stone with a rounded corner.
Cantilever: A projecting beam supported only at one end.
Cartridge: Disposable element containing filtering media and used in some pool filters.
Cartridge Filter: A filter that utilizes a porous element that acts as a filter medium.
Cement: A powdered substance of lime and clay generally mixed with water and aggregate to make concrete.
Check Valve: A valve that permits flow of water or air in only one direction through a pipe.
Checks (surface): Spider webbing pattern in a surface. Not all the way through, not an open crack.
Chlorine: A substance used to sanitize water by oxidizing (killing) bacteria; generally available in liquid, solid (tablets or sticks), and granular form.
Circuit Breaker: A device designed to open and close an electrical circuit manually, and to open a circuit automatically at a predetermined over current level, thus providing protection to the wiring and electrical components.
Circulation System: An arrangement of mechanical equipment and/or components designed to ensure even distribution of heat, chemicals, and filtration of water throughout the pool. Includes filters, heaters, pumps, chlorinators, piping, inlets, drains, skimmers and other appurtenances.
Coping: The cap on the wall that provides a finishing edge around the pool/spa. Can be formed, cast in place, precast, brick, stone, or pre-fabricated from metal or plastic material.
Cove: The radius that joins the floor and wall of a pool/spa.
Crack (surface): A repairable break in the surface, no major, not self-curing.
Crack (structural): A break or split which weakens the structural integrity of the pool.
Craze: See checks.
Decks: Those areas immediately adjacent to or attached to a pool or spa that are specifically constructed or installed for sitting, standing, or walking. Generally made of concrete, wood, or masonry.
Deep Area: Water depth areas exceeding five feet (5').
Diatomaceous Earth (DE): A white, powdery substance composed of tiny prehistoric skeletal remains of algae (diatoms), used as a water filtration media in DE filters.
Diatomaceous Earth (DE) Filter: Pool filter using DE as filtering method.
Diverter: Plastic or bronze adapter pipe that fits into a skimmer port to facilitate connection of a vacuum hose. The diverter can divert all suction to the skimmer, closing off the main drain or vice versa.
Erosion: 1. Act of destroying or dissolving by slow disintegration or wearing away. 2. In an erosion feeder, it is the way water dissolves the chemical being fed.
Etching: Corrosion of a surface by water that is acidic or low in total alkalinity or hardness.
Evaporation: Conversion of liquid molecules into vapor.
Expansive Soil: Clay soils that absorb moisture and swells, creating the potential for damage to a structure.
Feet of Head: The resistance in a hydraulic system based on the equivalent to the height of a column of water that causes the same resistance (100 feet of head equals 43 pounds per square inch). The total dynamic head in the sum of all resistances in a complete operating system.
Filter: Device for removing suspended particles from pool water.
Filter Cycle: Time of filter operation between backwashes.
Filter Element: A device within a filter tank designed to entrap solids and conduct water to a manifold, collection header, pipe, or similar conduit and return it to the pool, spa, or hot tub. A filter element usually consists of a septum and septum support or a cartridge.
Filter Media: Fine-grain materials in filter trap matter suspended in pool water.
Flow Rate: The volume of liquid flowing past a given point in a specified time period. Usually expressed as U.S. gallons per minute (gpm) or gallons per hour (gph).
Friction Head: Head specifically caused by friction or drag.
GPD: Gallons per day.
GPH: Gallons per hour.
GPM: Gallons per minute.
Hardness: Also called "calcium hardness". The amount of dissolved minerals (mostly calcium and magnesium) in a body of water. In unbalanced water, high levels cause scale and low levels corrode surfaces and equipment.
Heater: A fossil-fueled, electric or solar device to heat the water of a pool or spa.
Fossil-fueled heaters use natural, propane gas or fuel oil and utilize an open flame to heat a heat exchanger.