Pool Glossary
A-Z reference for pool owners, builders, and professionals
A. Water Chemistry & Treatment
Terms related to balancing and sanitizing pool water.
Acid Demand
The amount of acid required to lower pool water pH to the ideal range (7.2–7.6).
Alkalinity
A measure of water’s ability to resist pH changes. Ideal range: 80–120 ppm.
Bromine
A sanitizer alternative to chlorine, often used in hot tubs due to heat stability.
Calcium Hardness
The concentration of dissolved calcium in water; prevents corrosion or scaling (200–400 ppm ideal).
Chloramines
Irritating compounds formed when chlorine reacts with organic matter (e.g., sweat, urine).
Cyanuric Acid (CYA)
A stabilizer that protects chlorine from UV degradation. Ideal: 30–50 ppm.
Flocculant
A chemical that clumps particles for easier removal by vacuuming.
Oxidizer
A substance (e.g., chlorine, non-chlorine shock) that destroys contaminants through oxidation.
Phosphates
Nutrients that fuel algae growth; removed with phosphate removers.
Shock Treatment
Super-chlorination (10+ ppm) to eliminate contaminants and chloramines.
Total Dissolved Solids (TDS)
The cumulative concentration of dissolved substances in water. High TDS (>1,500 ppm) reduces clarity.
B. Pool Equipment & Systems
Components and machinery for pool operation.
Cartridge Filter
A filter using pleated fabric to trap debris; cleaned via hosing.
DE Filter (Diatomaceous Earth)
A high-efficiency filter using fossilized algae powder to trap particles as small as 1 micron.
Heat Pump
An energy-efficient device that transfers ambient heat to warm pool water.
Multiport Valve
A valve on filters that controls flow settings (e.g., backwash, rinse, recirculate).
Saltwater Generator
A system that converts salt into chlorine via electrolysis. Requires 2,500–4,500 ppm salt levels.
Skimmer
A wall-mounted device that removes surface debris before it sinks.
Variable-Speed Pump
An adjustable pump that reduces energy use by up to 80% compared to single-speed models.
Weir
The floating door on a skimmer that regulates water flow.
C. Construction & Design
Terms for building, materials, and pool types.
Coping
The cap or edging around a pool’s perimeter, often made of stone or concrete.
Gunite
A sprayable mix of cement, sand, and water used to build durable inground pools.
Pebble Tec
A premium pool finish combining smooth pebbles and epoxy for a natural aesthetic.
Semi-Inground Pool
A hybrid design partially buried for stability and aesthetic integration with landscapes.
Vinyl Liner
A flexible PVC membrane used as the water-retaining layer in vinyl-lined pools.
Zero-Depth Entry
A gradually sloping entry (like a beach) instead of traditional steps.
D. Maintenance & Troubleshooting
Common issues and solutions.
Backwashing
Reversing water flow to clean debris from a sand or DE filter.
Calcium Scaling
White, crusty deposits caused by high calcium hardness or pH.
Channeling
Uneven water flow in a sand filter due to compacted media; fixed by replacing sand.
Floccing
Using flocculant to clump suspended particles for vacuuming.
Leak Detection
Identifying water loss via pressure tests, dye testing, or electronic sensors.
Short Cycling
Frequent pump starts/stops due to clogged filters or incorrect sizing.
Turnover Rate
The time required to circulate the entire pool volume through the filter (ideally 6–8 hours).
E. Safety & Compliance
Regulations and best practices.
Anti-Entrapment Cover
A drain cover designed to prevent suction entrapment, mandated by the Virginia Graeme Baker Act.
Lifeguard Ratio
The number of swimmers per lifeguard (e.g., 1:25 for public pools).
Maximum Occupancy
The safe number of swimmers based on pool size (e.g., 1 person per 15 sq. ft.).
Self-Closing Gate
A safety gate that automatically latches to prevent unsupervised access.
VGB Compliance
Adherence to the Virginia Graeme Baker Pool & Spa Safety Act for drain safety.
F. Seasonal & Winter Care
Terms for off-season management.
Air Pillow
An inflatable device placed under ice to protect above-ground pools from freezing damage.
Closing Kit
A chemical bundle (shock, algaecide, antifreeze) for winterizing pools.
Solar Blanket
A UV-resistant cover that retains heat and reduces evaporation.
Winter Plugs
Devices inserted into skimmers and returns to prevent freeze damage.
G. Advanced Concepts
Technical terms for professionals.
Langelier Saturation Index (LSI)
A formula to assess water’s corrosive or scaling potential. Ideal range: -0.3 to +0.3.
Oxidation-Reduction Potential (ORP)
A measurement of water’s sanitizing power; higher ORP = better disinfection.
Hydraulic Efficiency
Optimizing pump and plumbing design to minimize energy waste.
TDS Meter
A device that measures total dissolved solids in water.
H. Common Problems & Fixes
Addressing algae, leaks, and more.
Black Algae
Stubborn algae with deep roots in pool surfaces; treated with copper-based algaecide.
Cloudy Water
Caused by poor filtration, imbalanced chemistry, or debris.
Filter Channeling
Uneven water flow in sand filters due to clumping; resolved by replacing media.
pH Bounce
Rapid pH fluctuations due to low alkalinity.
Sand Fouling
Contamination of filter sand by oils or debris; requires backwashing or replacement.
I. Specialty Pools & Features
Unique designs and add-ons.
Infinity Edge
A visual effect where water flows over a vanishing edge into a catch basin.
Lap Pool
A narrow, rectangular pool designed for swimming laps (typically 45–75 ft long).
Natural Pool
A chemical-free pool using plants and biofilters for water purification.
Spillover Spa
A connected hot tub that overflows into the main pool for aesthetic appeal.
Vanishing Edge
See Infinity Edge.
J. Health & Hygiene
Terms related to swimmer safety.
Cryptosporidium
A chlorine-resistant parasite causing gastrointestinal illness; removed via filtration.
Hot Tub Rash (Pseudomonas)
A bacterial infection from poorly sanitized water.
Swimmer’s Ear
An outer ear infection caused by bacteria in water; prevented with ear drops.
Urine Detector
A theoretical device to identify urine in pools (not widely used commercially).
K. Cost & Budgeting
Financial planning terms.
Cost Per Square Foot
A metric for estimating pool construction (e.g., 50–50–125/sq. ft. for concrete).
Resurfacing
Replacing a pool’s interior finish (plaster, pebble, etc.) every 10–15 years.
Total Cost of Ownership (TCO)
Long-term expenses including energy, chemicals, and repairs.
L. Measurement & Calculations
Units and metrics for pool care.
Gallons Per Minute (GPM)
Flow rate measurement for pumps and filters.
Parts Per Million (PPM)
Standard unit for chemical concentrations (e.g., chlorine, calcium).
Turnover Rate
The time required to filter the entire pool volume (ideally 6–8 hours).
M. Ecology & Sustainability
Eco-friendly practices and systems.
Biofilter
A plant-based filtration system used in natural pools.
Solar Ionizer
A device using copper/silver ions to reduce chlorine demand.
Variable-Speed Pump
Energy-efficient pump technology that lowers electricity costs.
N. Historical & Niche Terms
Lesser-known or outdated concepts.
Beaded Liner
A vinyl liner secured by a bead receiver track.
Diatomaceous Earth (DE)
Fossilized algae powder used in DE filters.
Hypochlorite
A family of chlorine compounds (e.g., calcium hypochlorite, sodium hypochlorite).