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Glossary of Pool and Hot Tub Terms

Here are some commonly used terms in the pool and hot tub / spa industry.

ACID DEMAND: - The amount of acid required by your pool water to achieve the proper pH level.

ACID: - A chemical that lowers pH and total alkalinity when dissolved in water by providing hydrogen ions. Hydrochloric acid and sodium bisulfate are two commonly usd acids.

ALGAE: - A microscopic one-celled plant organism. These organisms are continually introduced into the pool water by rain showers, wind, dust storms, etc...

ALGAECIDE: - A chemical used to kill algae

ALGAE SPORES: - Dormant algae residing in the atmosphere, which get introduced to the pool by rain, wind, dust storms, etc...

ALKALINE: - A condition when the pH of water exceeds 7.0 on the pH scale

BACTERIA: - An unseen, but dangerous organism that occurs in all water. Bacteria is controlled by disinfectants such as chlorine or bromine.

BASE DEMAND: - The amount of soda ash required to increase the pH level of pool water to the ideal range of 7.2 - 7.6.

BOTTOM DRAIN: - A water intake located at the bottom of the pool. The water is drawn into the filter from this before it is cleaned and returned to the pool.

BROMINE: - A sanitizer and disinfectant that kills bacteria and prevents algae.

CARTRIDGE FILTER: - A filter which utilizes a replaceable element and does not require backwashing.

CHLORINE:- A strong oxidizing agent for use as a sanitizer and disinfectant to kill bacteria and prevent algae.

CHLORINE, AVAILABLE:- Residual chlorine available to destroy bacteria on contact.

CHLORINE DEMAND: - The amount of chlorine required to destroy bacteria or algae.

CONDITIONER: - Also called Chlorine Stabilizer, Stabilizer, or Cyanuric Acid. A sun-screening chemical that reduces the loss of chlorine due to evaporation by the sun.

CORROSION: - A chemical reaction caused by unbalanced water which causes metals or minerals to dissolve.

CYANURIC ACID: - Also called Chlorine Stabilizer, Stabilizer, or conditioner. A sun-screening chemical that reduces the loss of chlorine due to evaporation by the sun.

D.E.: - Diatomaceous Earth: - A white powder added to an “earth” filter to clean the pool water of small organisms, dirt, etc...

ELECTRONIC IGNITION: - The ignition system on a pool heater that causes a heater to light through a spark ignition. There is no continuously burning pilot light in these heaters. This system is like your new gas stove where you hear the clicking sound when you are lighting it. Compare to Millivolt ignition.

FAST DISSOLVE TABLETS: -  A stabilized chlorine tablet that dissolves fast, typically within a half hours time when placed in the pools skimmer basket with the filter running.

FILTER: -  The part of the filter that cleans the water.

FREE CHLORINE RESIDUAL: - The active chlorine level in pool water after the chlorine demand is satisfied.

G.P.M. - GALLONS PER MINUTE: - Used to compare flow rates of various filter systems.

G.P.H. GALLONS PER HOUR: - Gallons per Hour - flow rate of pumps. (Compare to G.P.M.)

HARDNESS: -  The amount of calcium, magnesium, iron, carbonates, sulfates, chlorides, nitrates, phosphates, and silicates dissolved in the water. Scale deposits are formed when high levels of hardness are present in the water.

IN LINE CHEMICAL FEEDER: - An In-Line Chemical feeder has the main filter hose going through the chemical feeder. (Compare to Off-Line Feeder).

MAIN DRAIN: -  See Bottom Drain.

MILLIVOLT IGNITION SYSTEM: -  The ignition system on a pool heater which has a pilot light that runs continuously. Compare to Electronic Ignition.

MURIATIC ACID: -  Hydrochloric acid in liquid form used for lowering total alkalinity and pH of water.

OFF-LINE CHEMICAL FEEDER: - An off line chemical feeder is connected to a filter with smaller hoses that attach to the existing hoses of the filter system. (Compare to In-Line Feeder)

OTO: - An chemical used to determine the amount of chlorine in pool water.

P.P.M. - PARTS PER MILLION: - A measurement used to calculate how much chlorine, hardness, or alkalinity is present in pool water.

pH. : - The total of all acidic or alkaline particles in the water. The recommended range is 7.2 - 7.6.

PETROLEUM BASED LUBRICANTS:

PHENOL RED: - A chemical used to determine the pH level of water.

PRESSURE SIDE CLEANER: - A pressure side cleaner is a cleaner which is propelled around the pool by water pressure forced through the cleaner. The forced water is either from your filter system, or by a separate  "booster" pump  These cleaners pull a bag around behind them to catch dirt, leaves, and other debris from the pool. (Compare to Suction Side Cleaner)

PUMP: - The part of the filter that, along with the motor, determines the flow of water to the filter.

RETURN: - The part of the pool where the water is returned to the pool after it is filtered.

SAND FILTER: - Traditionally a filter that uses silica sand as the media for filtering out dirty and other impurities.New media is available to use in the sand filter to improve filtration. This includes zeo-sand and glass beads.

SCALE: - A crusty white, gray, or brownish substance that attaches itself to tile, plaster, or metal in pools. Normally caused by excessive water hardness.

SCRIM: - The weave of the material in winter covers. This is the number of weaves per inch in the cover. A 12 x 12 scrim is a stronger cover than an 8 x 8 scrim cover. Covers are generally sold as either 5 x 5, 8 x 8 or 12 x 12 scrim.

SHOCK TREATMENT: - Super Chlorination accomplished by adding 5 - 10 times the normal chlorine dose to help free up the free chlorine.

SKIMMER: - An inlet at the water level to catch large debris floating on the water.

SLOW DISSOLVE TABLETS: 

SODA ASH: - A chemical, Sodium Carbonate, that raises pH.

SODIUM BICARBONATE: - A chemical that raises the total alkalinity of water.

STABILIZER: - Also called Chlorine Stabilizer, Conditioner, or Cyanuric Acid. A sun-screening chemical that reduces the loss of chlorine due to evaporation by the sun.

SUCTION SIDE CLEANER: - A suction side cleaner is a cleaner which attaches to the skimmer or a dedicate vacuum line (on an inground pool) and draws the water directly into the filter. These cleaners work like your manual vacuum, except they move around the pool automatically. The dirt, leaves, etc... which are picked up are then filtered out of the water by your filter system

TEST REAGENTS: - Various chemicals used for testing pool water - chlorine levels, pH levels, etc...

TOTAL ALKALINITY: - The number of carbonates, bicarbonates, and hydroxides, measured on p.p.m., that are present in pool water.

TURNOVER: - The period of time required to circulate a volume of water equal to the water volume of the pool.

VELOCITY: - The rate of movement of water measured in gallons per minute.