Pool Chemistry Entity Graph

The canonical semantic layer for WaterBalanceTools. 104 entities across 10 types, with 141 aliases and 420 explicit relationships.

All Entities by Type

Chemical (15)

  • Free Chlorine — The active, unsaturated chlorine available to sanitize pool water.
  • Combined Chlorine — Chlorine that has reacted with contaminants and is no longer effective for sanitization.
  • Total Chlorine — The sum of free chlorine and combined chlorine in pool water.
  • Bromine — A halogen sanitizer commonly used in hot tubs that remains effective at higher pH and temperatures.
  • Cyanuric Acid — A chemical stabilizer that protects chlorine from UV degradation in outdoor pools.
  • Calcium Hardness — The concentration of dissolved calcium in pool water, affecting scaling and corrosion tendency.
  • Salt — Sodium chloride dissolved in pool water to enable chlorine generation by a salt chlorinator.
  • Total Dissolved Solids — The cumulative concentration of all dissolved matter in pool water.
  • Phosphate — A nutrient compound in pool water that can fuel algae growth.
  • Copper — A metal that can enter pool water from ionizers, algaecides, or corroded equipment, causing green staining.
  • Iron — A metal dissolved in pool water that causes rust-brown staining when oxidized.
  • Manganese — A dissolved metal that causes black or purple staining in pool water.
  • Hydrogen Peroxide — An oxidizer used in non-chlorine pool systems and as an emergency chlorine neutralizer.
  • Ozone — A powerful oxidizer generated on-site and injected into pool water as a supplemental sanitizer.
  • Biguanide — A chlorine-free sanitizer system using polyhexamethylene biguanide (PHMB) as the primary disinfectant.

Measurement (10)

  • pH — The measure of hydrogen ion concentration indicating acidity or alkalinity of pool water.
  • ORP — Oxidation-Reduction Potential — an electrical measurement of water's sanitizing capacity.
  • Temperature — Water temperature in °F or °C, affecting chemical reactions, chlorine demand, and comfort.
  • Total Alkalinity — The capacity of water to resist pH changes — a pH buffer.
  • Langelier Saturation Index — A composite score indicating whether water is balanced, corrosive, or scale-forming.
  • Gallons — US liquid gallon — the standard unit of pool volume measurement.
  • Liters — SI unit of volume — 1 US gallon equals approximately 3.785 liters.
  • Parts Per Million — The standard unit for measuring chemical concentrations in pool water.
  • Flow Rate — The volume of water the pump moves per minute — a key factor in turnover rate.
  • Turnover Time — The time required for the pump to circulate the entire pool volume through the filter once.

Equipment (10)

  • Pool Pump — The motor and impeller assembly that circulates water through the filtration and chemical treatment system.
  • Sand Filter — A filter using silica sand to trap particles down to 20–40 microns.
  • Cartridge Filter — A filter using pleated polyester cartridges to trap particles down to 10–15 microns without backwashing.
  • DE Filter — A diatomaceous earth filter offering the finest filtration (3–5 microns) of any pool filter type.
  • Skimmer — A wall-mounted intake that removes floating debris from the pool surface before it sinks.
  • Pool Heater — A device that raises water temperature using gas, electric heat pump, or solar energy.
  • Salt Chlorinator — An electrolytic cell that converts dissolved salt into hypochlorous acid to sanitize pool water.
  • Automatic Chlorinator — An inline or offline device that dispenses trichlor tablets continuously to maintain free chlorine.
  • Chemical Feeder — A device that automatically dispenses pool chemicals at a controlled rate.
  • Pool Cover — A cover that reduces evaporation, heat loss, debris entry, and UV degradation of chemicals.

Process (11)

  • Shock Treatment — Adding a large dose of chlorine or non-chlorine oxidizer to destroy combined chlorine, algae, and contaminants.
  • Breakpoint Chlorination — Adding chlorine at 10× the combined chlorine level to destroy all chloramines.
  • Backwashing — Reversing water flow through a sand or DE filter to flush trapped debris to waste.
  • Winterization — The process of closing a pool or hot tub for the winter to prevent freeze damage.
  • Pool Opening — The spring start-up process to prepare a pool for the swimming season.
  • Water Replacement — Partially or completely draining and refilling pool or spa water to reduce dissolved compound levels.
  • Filtration — The continuous mechanical removal of suspended particles from pool water.
  • Water Testing — Measuring pool water chemistry parameters using test strips, liquid kits, or digital testers.
  • Sanitizing — Maintaining an adequate residual disinfectant to destroy pathogens in pool water.
  • Oxidation — The chemical destruction of organic compounds, combined chlorine, and contaminants in pool water.
  • Water Balancing — The process of adjusting all chemistry parameters to achieve a stable, non-corrosive, non-scaling LSI.

Resource (8)

Problem (13)

  • Cloudy Water — Water that lacks clarity due to suspended particles, chemical imbalance, or filtration issues.
  • Green Water — Pool water discolored green by algae bloom due to insufficient free chlorine.
  • Foaming — Persistent foam on pool or spa water surface caused by surfactants, high TDS, or algaecide.
  • Scaling — White or grey mineral deposits on pool surfaces and equipment caused by over-saturated water.
  • Corrosion — Damage to pool surfaces and metal equipment caused by corrosive (low LSI) water.
  • Algae — Plant-like organisms that grow in pool water when free chlorine is insufficient.
  • Strong Chlorine Smell — A pungent chlorine odor caused by chloramines, not excess chlorine.
  • Eye Irritation — Swimmer eye irritation caused by chloramines or pH imbalance.
  • Skin Irritation — Swimmer skin irritation caused by pH imbalance, chloramines, or high disinfectant levels.
  • Low Chlorine — Free chlorine below the minimum effective level for the current CYA concentration.
  • High Chlorine — Free chlorine above 5 ppm causing bleaching, eye/skin irritation, and swimmer discomfort.
  • Low pH — Pool water pH below 7.2, causing corrosion, eye irritation, and equipment damage.
  • High pH — Pool water pH above 7.8, reducing chlorine effectiveness and promoting scale formation.

Pool Type (10)

  • Swimming Pool — A permanent or above-ground body of water designed for recreational swimming.
  • Saltwater Pool — A pool that uses a salt chlorinator to generate chlorine on-site from dissolved sodium chloride.
  • Indoor Pool — A pool housed inside a building, requiring ventilation management and no CYA.
  • Outdoor Pool — A pool exposed to direct sunlight and weather, requiring CYA stabilization of chlorine.
  • Hot Tub — A small, heated pool (75–500 gallons) used for relaxation and hydrotherapy.
  • Swim Spa — A larger spa (12–20 ft) with jets for swimming in place and hydrotherapy.
  • Commercial Pool — A public or semi-public pool subject to health department regulations and inspection.
  • Vinyl Pool — A pool with a vinyl liner surface requiring lower calcium hardness targets.
  • Fiberglass Pool — A pre-molded pool with a smooth fiberglass surface requiring moderate calcium levels.
  • Concrete Pool — A plastered or pebbled concrete pool requiring higher calcium hardness (200–400 ppm).

Chemical Product (10)

  • Liquid Chlorine — Sodium hypochlorite solution (10–12.5%) — the most commonly used liquid pool sanitizer.
  • Calcium Hypochlorite — Granular or tablet pool shock available at 65% or 73% available chlorine (cal-hypo).
  • Dichlor — A stabilized granular shock (56–62% available chlorine) that adds both chlorine and CYA.
  • Trichlor Tablets — Stabilized chlorine tablets (90% available chlorine) for use in automatic chlorinators and floaters.
  • Muriatic Acid — Hydrochloric acid (31.45%) used to lower pH and total alkalinity in pool water.
  • Soda Ash — Sodium carbonate — used to raise pH in pool water.
  • Baking Soda — Sodium bicarbonate — the standard product for raising total alkalinity in pool water.
  • Calcium Chloride — Used to raise calcium hardness in pool water.
  • Stabilizer / CYA Granules — Granular cyanuric acid product used to raise CYA to the target stabilizer level.
  • Pool Salt — High-purity sodium chloride (99.8%+) for use in saltwater pool systems.

Organization (6)

  • CDC — Centers for Disease Control and Prevention — a key authority on healthy swimming and recreational water illness.
  • EPA — U.S. Environmental Protection Agency — regulates disinfectants including pool chemicals.
  • PHTA — Pool & Hot Tub Alliance — the primary industry trade association for pool and spa professionals.
  • NSF International — NSF International — certifies pool and spa equipment and chemicals to safety standards.
  • Taylor Technologies — Taylor Technologies — manufacturer of professional pool test kits and the standard reference for pool chemistry calculations.
  • LaMotte — LaMotte Company — manufacturer of professional water testing equipment for pool and spa use.

Unit (11)

  • ppm — Parts per million — the standard concentration unit for pool chemistry.
  • mg/L — Milligrams per liter — numerically identical to ppm in aqueous solutions.
  • US Gallons — US liquid gallon — the primary volume unit for pool calculations in North America.
  • Liters — SI unit of volume. 1 US gallon = 3.785 liters.
  • °F — Degrees Fahrenheit — the standard temperature unit for pool and spa temperature in North America.
  • °C — Degrees Celsius — the SI temperature unit used in metric countries.
  • Minutes — Unit of time — used for pump turnover calculation and wait times after chemical additions.
  • Hours — Unit of time — used for turnover rate and pump run time calculations.
  • Days — Unit of time — used for maintenance scheduling and chemical activity timelines.
  • Weeks — Unit of time — used for maintenance scheduling (weekly testing, weekly shock).
  • Months — Unit of time — used for seasonal maintenance intervals and hot tub water change schedules.