Pool Glossary A-Z


ACID: When speaking of pools, acid refers to muriatic acid, a diluted hydrochloric acid.

ACID DEMAND: The amount of acid required to bring high pH or total alkalinity down to their proper levels. This is measured by an acid demand test.

ACID RAIN: Rain that has a low pH caused by air pollution.

ACRYLIC: A thermoplastic material that is extrudable or injectable into multiple shapes and surfaces.

AIR-RELIEF VALVE: A valve on the top of a filter tank that is manually operated to relieve pressure inside the filter or to remove air trapped in the filter. This is commonly referred to as a pressure-relief valve.

ALGAE: Living and breathing organisms that come in various shapes and colors. It can appear in your pool as green, blue-green, black, pink, yellow, or any color in between. It can form on your pool’s surface or bloom suspended in the water. It can negatively affect your pool.

ALGAECIDE: Algaecide is intended to kill algae blooms. Algaecides are not meant to replace your normal pool maintenance but only to be used when you specifically need an algae treatment product. There are a variety of algaecides available: copper and silver compounds, poly-quat compounds, chlorine enhancers, and herbicides.

ALGAESTAT: Algaestat is what you use in your pool before needing an algaecide to prevent the genesis and growth of algae.

ALKALI: Alkali raises the pH and alkalinity when added to water.

ALKALINITY: Refers to the pH buffering capacity of water. It is usually expressed in terms of an equal concentration of calcium carbonate.

ALUMINUM: A member of the poor metal group of chemical elements and is silvery white.

ALUMINUM SULFATE: Aluminum sulfate is a flocculent which attracts any suspended particles in the water together. It sinks everything to the bottom to clean up green or cloudy pools; everything can then be vacuumed out. Commonly referred to as “alum”.

AMMONIA: Ammonia is a chemical compound of nitrogen of hydrogen. It combines with free chlorine in pools to form chloramines or combined chlorine.

ANTI-FOAM: Anti-foam is simply a chemical compound added to water to reduce foam. It does not remove the source of the foam.

AUTOMATIC POOL CLEANER: An automatic vacuuming system used to clean dirt and debris from inside your pool without any manual labor. Some work on low-voltage electricity and others work on pump suction. Some automatic pool cleaners are programmable or controlled via remote.

AVAILABLE CHLORINE CONTENT: This is a term used to compare oxidising power that chlorine products have with gas chlorine.

AVAILABLE CHLORINE: This refers to the amount of free chlorine in the water that is available to sanitize or disinfect. It is sometimes called residual chlorine or free available chlorine.

BACKWASH: Also known as ‘backwashing’. This is the process of cleaning the filter or filter elements by the reverse flow of water through the filter.

BACTERIA: Bacteria are single celled organisms. They come in various forms and can cause infections or disease.

BASE: A base refers to a chemical of alkaline nature that counteracts the pH of an acid. Bases are common to use around the pool; some use soda ash, sodium bicarbonate, or sodium carbonate. They are the opposite of an acid and used to help balance your pool’s water.

BOOSTER PUMP: Booster pumps are sometimes used alongside filter pumps to power some automatic pool cleaners.

BROMIDE: Bromide is usually in the form of bromine salt. It is used as a disinfectant in swimming pools.

BUFFER: A buffer is a chemical added to the pool that results in resistance to changes in pH. Sodium bicarbonate is an example of a buffer, it will increase your pool’s total alkalinity. This increases the buffering capacity of the pool.

CALCIUM: A soft alkaline earth metal.

CALCIUM HARDNESS: Calcium hardness is the calcium content of the water. If this level becomes too low the water can be corrosive. It it’s too high, the water can form scale. It’s important to keep it at a balanced level.

CAPACITY: The total gallons of water your pool can hold.

CHLORAMINES: A chemical compound formed when chlorine combines with nitrogen compounds like ammonia or perspiration. This can cause eye and skin irritation and low sanitizing ability.

CHLORINE: A chemical element that exists as part of a chemical compound. It’s used to disinfect pool and spa water.

CLARIFIER: A chemical that neutralizes suspended particles in water.

CLARITY: Clarity is the degree of transparency of the pool’s water.

CONTAMINANTS: An undesirable substance in water such as: organic material, inorganic material, soluble materials, insoluble materials, or microbiological organisms.

CORROSION: It is the scratching, pitting, or eating away of material.

COVER: Pool covers rest on the edge of the pool deck and does not have contact with the water. Typically used when pools close for the season.