A Consumer’s Guide to Common Pool Terms

Make Sense of Pool Industry Lingo with These Common Pool and Water Chemistry Terms


These common pool terms will help you better understand building and maintaining your pool.

Basic Water Chemistry Terms

Algae – Microscopic plant-like organisms that contain chlorophyll. Carbon dioxide (CO2) and sunlight cause algae to photosynthesize and grow. It is introduced by rain or wind and grows in colonies producing nuisance masses. Although it does not cause disease, algae can harbor bacteria and is slippery. The most common pool types and black, blue-green, green and mustard (yellow or drawn). Pink or red-colored algae-like organisms exist but are bacteria and not algae. Maintaining proper sanitizer levels, shocking and super chlorination will help prevent its occurrence.

Algaecide (Also called algicide) – Chemicals, natural or synthetic, that destroy or control algae.

Alkalinity – Total alkalinity is a measure of the pH-buffering capacity of water, or the water’s resistance to change in pH. Composed of the hydroxides, carbonates and bicarbonates in the water. One of the basic water tests necessary to determine water balance.

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.

Bacteria – Various forms of single-celled microorganisms which can be undesirable or potentially disease-causing. Bacteria are controlled by chlorine, bromine or other sanitizing and disinfecting agents.

Bactericide – A substance, either chemical or elemental, that destroys or controls bacteria.

Balanced Water – The correct ratio of mineral content and pH level that prevents the water from being corrosive or scale forming.

Buffer – Water’s resistance to change in pH or a substance or compound that stabilizes the pH value of a solution.

Chlorine – Any type of chlorine compound used as a disinfectant in swimming pool and spa water or used to destroy or control bacteria and algae. Chlorine also oxidizes ammonia and nitrogen compounds (swimmer and bather waste).

Conditioner – Chemically, conditioner is cyanuric acid. It slows down the degradation of chlorine in the water by sunlight. Minimum level is 10 ppm. Too much does not slow down chlorine activity or effectiveness. Conditioner does not protect bromine from sunlight.

Conditioner – Chemically, conditioner is cyanuric acid. It slows down the degradation of chlorine in the water by sunlight. Minimum level is 10 ppm. Too much does not slow down chlorine activity or effectiveness. Conditioner does not protect bromine from sunlight.

Defoamer – Also called anti-foam – A chemical added to the water to make the suds or foam go away. These products do not remove the source of the sudsing. Most often, the water must be drained and refilled to remove the soaps, oils and other causes of foaming. Shocking and super chlorination may help prevent foaming.

Dissolved Solids – Total dissolved solids (TDS) is the measure of the total amount of dissolved matter in water. Some solids include calcium, magnesium, carbonates, bicarbonates, sodium, chlorides and metals. High levels can cause corrosion, colored water or salty taste. Maximum level is usually 2500 ppm for pools. Maximum level for spas is 1500 ppm over starting level.


Basic Pool Terms

Air Blower – Mechanical devices for bubbler rings or hydrotherapy jets in a spa that force air through holes in the floor.

Automatic Cover – A electronically powered pool cover, usually for use on rectangle shaped pools. Part of the fence code requirements can be met if the cover fits tightly over the swimming pool, spa or other body of water over 24 inches deep. Automatic covers are not only used as a pool cover but also for solar heating and pool maintenance as well.

Automatic Pool Cleaner – Cleans the bottom of pools by collecting debris through a vacuum or stirring it to be pushed through the filter.

Backwash – Thoroughly cleaning the filter by reversing the flow of water through the filter with the dirt and rinse water going to waste.

Cartridge – The filter medium in cartridge filter usually made of porous paper or polyester.

Cartridge Filter – Water filtration system that uses a replaceable porous element to catch solids.

Cascade – Water stream coming from a raised spa or wall.

Centrifugal Pump – A pump that’s power comes from creating pressure in water by the velocity formed through centrifugal force. Contains a impeller fixed on a rotating shaft, enclosed in a casing or volute that has an inlet and a discharge connection.

Chlorinator – Often a canister or floater filled with tablets of chlorine this mechanical or electrical device dispenses chlorine at a controlled rate.

Conditional Lien Release – A document signed by a contractor, supplier or subcontractor evidencing that the job has been paid in full, subject to the check for the services clearing the bank.

Contractor’s Bond – A $12,500.00 bond a pool contractor must post with the Contractors’ Board in California, used to settle disputes the contractor will not take care of himself. Posted via as an insurance policy or in cash, generally contractors who post cash bonds are more financially stable. Most states require a contractor’s bond.

Contractor’s License – A valid contractor’s license, C-53 for California licensing, required to do business as a swimming pool contractor. Without this licensing a contractor can not build a pool or the surrounding landscape.

Coping – Typical 12 inch finishing around a pool’s edge.

Coupling – A fitting used to connect two pieces of plumbing pipe.

Hard Top Cover – A cover that rests on the lip (coping) of a pool or spa deck used to barrier swimmers and the elements and sometimes used as a thermal protector.

Solar Cover – A cover that uses solar energy to heat a pool as well as keep out debris.

Winter Cover – A cover used to keep out swimmers and debris when a pool is closed for the season.

Decking – The area surrounding a swimming pool, usually concrete but can be made from other decking material as well.

Diverter Valve – Directs or redirects the flow of water. For example, it may be used on pool/spa combinations to allow the use of the spa and then switch the flow back to the pool.

Drain – The plumbing fitting located on the suction side of the pool pump, usually the main drain is located in the deep end, that allows water to be recirculated instead of wasted. The main drains are required to split into a minimum of two suction points at least 36 inches apart.

Electric Panel – The electric service for a swimming pool or spa must originate from the property’s main electric panel or from a properly sized sub panel, in older homes the electric service may not support a pool or spa. In this case, a new one will need to be installed.

Excavation – Removal of the soil in order to create the depth of the swimming pool. This is often a area of mis-communication between a home owner and contractor, pay attention to excavation specifics in a contract.

Filter – A tank usually containing cleanable cartridges used to clean a pool or spa.

Fountain – A water feature the spouts water and often has a man-made appearance.

Freestanding – Pool walls built to stand without the surrounding soil for support.

Gas Line – The proper gas system required to run a natural gas or propane swimming pool or spa heater that comes from either the natural gass meter or propane tank.

Gunite – A dry mixture of sand and cement with water added at the nozzle applied to the swimming pool shape by air pressure.

Inspection – Inspection of the work being completed on you pool by the city. The contractor is to periodically call for these inspections. The inspector will visit the project within 24 to 48 hours from request. The home owner may not know about the inspection but the inspector will visit through the same access workers have to the home. If there is a complication and the inspector has to reschedule the inspection there may be fee that the contractor usually pays. Homeowners are expected to leave proper access to the work site available.

Ledger Stone – Stone facing on a surface surrounding a pool, typically requiring more materials and labor.

Pebble finish – A upgraded finish for pool bottoms that can be found in different colors.

Permits – Obtained by the contractor through a plan check by zoning, planning, engineering and building departments before a pool is built.

Plaster – A pools standard finish for the bottom and sides of a swimming pool usually in white but sometimes installed in other colors.

Scupper- A design element that allows water to flow from a spa or elevated fountain into a pool.

Shotcrete – A wet mix pool plaster that is applied pneumatically to the pool frame. It can be applied to any form or shape, including overhead structures.  

Steel reinforcement – Reinforcing bar (rebar) within the swimming pool structure approved by the swimming pool contractor. The contractor must disclose any conditions requiring special engineering, if not and the inspection fails, the home owner will have to pay for additional engineer to fix problems.

Stone facing – Stone facing on walls raised bond beam or at swimming pool or spa water line installed flat with grout joints separating each piece.

Unconditional lien release – A document to prove the job is paid in full signed by contractor, supplier or subcontractor.

Waterfall – A water feature made of stone, boulders, or other various forms.

Waterline tile – The material used to cover the top vertical six inches of a pool. Half way up the waterline tiles indicate the suggested water line.