Glossary of Swimming Pool Terms

Not sure what a term means? Use this glossary to understand common pool-related terms and concepts.

Complete Pool Glossary

A

• Acid: A chemical used to lower the pH level of pool water.
• Acid Demand: The amount of acid needed to lower pH to the desired level.
• Acid Wash: A process that removes stains, algae, and calcium buildup from pool surfaces using a diluted acid solution.
• Aeration: The process of increasing oxygen levels in water, often used to raise pH.
• Aggregate Finish Pool Surface: A pool surface made of plaster mixed with quartz, pebbles, or glass beads.
• Air Pillow for Winter Pool Covers: An inflatable cushion placed under a winter pool cover to prevent ice damage and distribute pressure evenly.
• Alkalinity Increaser: a chemical used to raise total alkalinity in pool water, helping to stabilize pH levels and prevent fluctuations.
• Algae Bloom: A rapid growth of algae in the pool, often caused by poor sanitation or chemical imbalance.
• Algaecide: A treatment designed to kill and prevent algae growth.
• Ammonia: A chemical that can combine with chlorine to form chloramines, reducing sanitization effectiveness.
• Ascorbic Acid Treatment: A method used to remove metal stains from pool surfaces.

B

• Backwashing: The process of cleaning a filter by reversing the flow of water.
• Bather Load: The number of people using a pool at a given time, impacting chemical demand.
• Black Algae: A stubborn type of algae that forms deep-rooted colonies on pool surfaces, making it difficult to remove.
• Borates in Pool: Chemicals used to stabilize pH and provide a sparkling water effect.
• Breakpoint Chlorination: A process where enough chlorine is added to eliminate combined chlorine.
• Breakdown of Bleach Over Time by Storage Temp: Information on how bleach potency decreases based on storage conditions.
• Bromine: A gentle, low-odor sanitizer ideal for hot tubs and indoor pools, effective even at high temperatures.
• Bromine Feeder: an automatic dispensing system that gradually releases bromine sanitizer into hot tubs and pools for continuous sanitation.
• Bonding & Grounding: Are electrical safety measures designed to prevent shock hazards in pools.

C

• Calcium Hardness: The level of dissolved calcium in pool water.
• Calcium Hypochlorite: A granular or tablet form of chlorine used for sanitization.
• Calcium Increaser: a chemical used to raise calcium hardness levels in pool water to prevent corrosion and protect pool surfaces.
• Cartridge Filter: A type of pool filter that uses a replaceable cartridge to trap debris.
• CC (Combined Chlorine): Chlorine that has combined with contaminants and is no longer effective as a sanitizer.
• Clarifier: Improves water clarity by clumping fine particles for easier filtration.
• Chlorine Demand: the amount of chlorine required to effectively sanitize pool water and break down contaminants.
• Chlorine Lock: a condition where high levels of cyanuric acid (CYA) reduce the effectiveness of chlorine, preventing proper sanitization.
• Chloramines: Byproducts formed when chlorine binds with contaminants, causing strong odors and irritation.
• Coagulant: a pool chemical that helps tiny particles clump together, making them easier to remove through filtration.
• Copper Algaecide: a pool treatment that contains copper ions to kill and prevent algae growth.
• CPO Training: Certified Pool Operator training for pool professionals.
• CSI and LSI: Calculations used to determine if pool water is balanced, corrosive, or scaling.
• CYA (Cyanuric Acid): A stabilizer that protects chlorine from UV degradation.
• CYA Chlorine Relationship: How stabilizer levels affect chlorine efficiency.

D

• Diatomaceous Earth (DE): A fine powder used in filters to trap ultra-fine particles, ensuring crystal-clear pool water.
• Dichlor Shock: a stabilized chlorine treatment used for routine pool maintenance and algae prevention.

E

• Efflorescence: A crystalline deposit of salts often found on pool tiles or surfaces.
• Enzyme Cleaner: A biological treatment that breaks down oils and organic waste in pool water.

F

• Flocculant: A chemical that binds fine particles together so they can be removed from the water by vacuuming.
• Floating Chemical Dispenser: a device that holds chlorine or bromine tablets and slowly releases them into the water to maintain proper sanitization levels.
• Free Chlorine (FC): The active and available chlorine that sanitizes pool water.
• Filter Cycle: The length of time a pool filter runs before requiring cleaning or backwashing.
• Filter Media: The material inside a filter (sand, DE, or cartridge) that captures debris.

H

• Hydraulic Balance: Refers to the proper distribution of water flow in a pool system to ensure efficient circulation and filtration.
• Hot Tub Defoamer: a chemical used to eliminate excessive foam buildup caused by soaps, oils, and personal care products in spa water.

I

• Infinity Edge Pool: A design where water flows over an edge, creating a visual effect of water extending to the horizon.\
• Iron Remover: a pool chemical designed to eliminate excess iron and other metals from pool water to prevent staining and discoloration.

L

• Leaf Canister: An attachment for a pool vacuum that traps large debris before it reaches the pump basket.
• Langelier Saturation Index (LSI): A formula used to determine if pool water is corrosive, balanced, or scaling.
• Liquid Chlorine: A concentrated form of chlorine used for shock treatments or daily sanitization.

M

• Main Drain: A suction outlet located at the bottom of a pool that assists in water circulation and debris removal.
• Multiport Valve: A valve that directs the flow of water in sand and DE filters for various functions like backwashing and rinsing.
• Muriatic Acid in Pools: A liquid acid used to lower pH and alkalinity levels in pool water, ensuring balanced water chemistry and preventing scale formation.
• Mustard Algae: A chlorine-resistant yellow algae that clings to pool surfaces and is often mistaken for pollen or dirt.

N

• Non-Chlorine Shock: An oxidizing treatment that removes contaminants from pool water without adding chlorine.

O 

• Oxidation-Reduction Potential (ORP): A measure of a pool's ability to oxidize contaminants and kill bacteria.
• Oxidizer: a pool chemical used to break down organic contaminants, remove chloramines, and improve water clarity.
• Ozone System: A water purification system that uses ozone gas to oxidize contaminants.

P

• Pebble Tec Finish: A durable pool surface made of exposed aggregate, providing a natural texture and enhanced longevity.
• Pink Slime (Bacteria): A bacterial growth in pools and spas that appears as a pink or reddish-colored slime.
• Pressure Gauge: A device used to monitor filter pressure and determine when cleaning is necessary.
• Plaster Crazing: Fine cracks that appear on plaster pool finishes due to curing or chemical imbalance.
• pH: A measure of how acidic or basic the pool water is.
• pH Stabilizer: A chemical that helps maintain consistent pH levels, preventing rapid changes and ensuring balanced water chemistry.
• pH TA Relationship: The connection between pH and total alkalinity in maintaining water balance.
• Phosphates: Nutrients that promote algae growth in pool water, leading to potential water clarity and maintenance issues.
• Phosphate Removers: Chemicals that reduce phosphate levels, which algae use as a food source.
• Pool Chemistry: The science of maintaining water balance, sanitization, and clarity.
• Pool Cover Pump: a device designed to remove excess water from pool covers during the off-season.
• Pool Heat Pump: an energy-efficient heating system that extracts heat from the air and transfers it to pool water.

S

• Saltwater Generator: It converts salt into chlorine to sanitize pool water without the need for traditional chlorine products.
• Salt Cell Cleaner: a chemical solution used to remove scale buildup and deposits from saltwater generator cells, ensuring efficient chlorine production.
• Scale Formation: A buildup of calcium and minerals on pool surfaces and equipment.
• Scale Inhibitor: a pool chemical designed to prevent calcium and mineral buildup on pool surfaces, equipment, and plumbing.
• Sequestrant: A chemical that prevents metal stains and scaling in pools.
• Skimmer Basket: A mesh container inside the skimmer that captures debris before it reaches the pump and filter.
• Slurry Pump: a specialized pump designed to remove thick debris, sediment, and sludge from pools and spas.
• Sodium Hypochlorite: The liquid form of chlorine often referred to as bleach.
• Spa Air Blower: a motorized component that injects air into spa jets, creating a bubbling effect for a relaxing experience.
• Spillover: A design feature where water overflows from a raised spa into an adjacent pool, creating a continuous flow effect.
• Stain Lufter: a specialized chemical used to remove organic and metal-based stains from pool surfaces.
• Shock Treatment: Also known as pool shocking, involves adding a large dose of chlorine or other oxidizers to the pool water to destroy contaminants, eliminate chloramines, and restore water clarity.
• Surface Blistering: Refers to the formation of raised bubbles or bumps on a pool's plaster or fiberglass surface, often caused by water pressure or material defects.

T

• TA (Total Alkalinity): Helps maintain pH stability in pool water.
• TDS (Total Dissolved Solids): The sum of all minerals, chemicals, and debris dissolved in water.
• Tile Scaling: The buildup of calcium deposits on pool tiles, often caused by high calcium hardness or imbalanced water chemistry.
• Trichlor Tablets: Slow-dissolving, stabilized chlorine products that sanitize pool water while adding Cyanuric Acid (CYA) for UV protection.
• Total Chlorine: The sum of free chlorine and combined chlorine present in pool water.
• Turnover Rate: The time required for all the water in a pool to pass through the filtration system once.

U

• UV Sanitizer: A system that uses ultraviolet light to neutralize bacteria and algae in pool water.

V

• Variable Speed Pump: An energy-efficient pool pump that allows adjustable flow rates to optimize filtration and circulation.
• Virginia Graeme Baker Act (VGBA): is a U.S. law that mandates anti-entrapment drain covers for pools and spas to prevent accidents.

W

• Waterline Tile: Tiles along the top edge of the pool that help prevent staining and scaling.
• Water Evaporation Rate: Is the speed at which water naturally evaporates from a pool due to environmental factors.
• Winter Cover Anchors: Devices used to secure pool covers in place during winter months, preventing wind and debris from entering the pool.
• Winterizing Kit: A set of chemicals and equipment used to prepare pools for colder temperatures and prevent damage during the off-season.

Z

• Zinc Anode: A sacrificial metal used to reduce corrosion in pools with saltwater systems.

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