Pool Fountain - Gold Medal Pools & Outdoor Living

Glossary of Terms


ACID DEMAND – Acid required to destroy excessive amounts of alkalinity.

ACIDIC WATER – The condition of water that contains a sufficient amount of acid to lower the pH 7.0. Water with a pH below 7.0.

ALGAE – Microscopic plants that contain chlorophyll and live floating or suspended in water. They also may be attached to structures or other submerged surfaces. Algae produces oxygen during sunlight hours and uses oxygen during the night hours. These organisms are continually introduced into the pool by winds, dust storms, rain showers, etc. Besides being unsightly, pool contaminated with algae is unsanitary.

ALGAECIDE – Any substance or chemical specifically formulated to kill algae.

ALKALINITY – The capacity of water to neutralize acids. Alkalinity is expressed in parts per million (ppm). Alkalinity is not the same as pH because water does not have to be strongly basic (high pH) to have a high alkalinity. Alkalinity is a measure of how much acid can be added to water without causing a great change in pH.

ALKALINE – A condition of water which contains a sufficient amount of alkali substance to raise the pH above 7.0.

BACKWASHING – The process of reversing the flow of water back through the filter media to remove entrapped solids.

BACTERIA – Bacteria are living organisms, microscopic in size, which usually consist of a single cell. Most bacteria use organic matter for their food and produce waste products as a result of their life processes. Invisible living germs that can be harmful to swimmers.

BTU (British Thermal Unit) – a measure of heat energy. As a general rule, a pool will raise approximately 1 degree per hour and a spa will raise approximately 1 – 2 degrees per 5 minutes. The items that will affect this time frame are the size and depth of the pool/spa; the size of the pool heater and the distance the pool/spa is from the pool equipment.

CALCIUM – Metal iron contained in water can form salts such as calcium
carbonate. Calcium carbonate in sufficient amounts can cause cloudiness or scaling. It usually exists because of improper balance of pH.

CALCIUM HYPOCHLORITE (CAL HYPO) – Type of granular chlorine used to shock pools. There is an available chlorine level of 65%, calcium level of 18.2% and a pH level of 10.0 – 11.0.

CHECK VALVE – A special valve with a hinged or spring loaded disc that opens in the direction of normal or excessive flow. It is forced shut when water flow attempts to go in the reverse direction.

CHELATION – A chemical complexional (forming or joint together) of a metallic ion (such as iron or copper) with certain organic compounds, such as EDTA (ethylene diamine tetracetic acid). Chelation is used to prevent the precipitation of metals (calcium, copper etc.)

CHLORINE (available) – Residual chlorine that is available to destroy bacteria on contact.

CHLORAMINE – Available chlorine that combines with nitrogen compounds in the water to form chloramines (this has far less potential to destroy bacteria than free chlorine).

CHLORINE DEMAND – Chlorine demand is the difference between the amount of chlorine added to water and the amount of residual chlorine remaining after a given contact time. Chlorine demand may change with dosage, time, temperature, pH, and the nature and amount of the impurities in the water.

CHLORINE (free) –Chlorine known as hypochlorous acid that has not reacted with other materials to form combined chlorine.

CHLORINE RESIDUAL – That chlorine remaining in pool water after demand has been satisfied.

CORROSION – The gradual decomposition or destruction of a material by chemical action, often due to electrochemical reaction. Corrosion may be caused by (1) stray current, (2) galvanic corrosion caused by dissimilar metals, (3) concentrated oxidation, or (4) an acidic solution.


DIATOMACEOUS EARTH (DE) – A fine, siliceous (made of silica) earth composed mainly of abrasive skeletal remains of diatoms.

DILUTE SOLUTION – A solution that has been made weaker usually by the addition of water (H2O).

DPD – A method of measuring the chlorine residual in water. The residual may be determined by either titrating or comparing a developed color with color standards.

ELECTROLYTIC CONVERSION – Generating bromine or chlorine from a sodium bromide or sodium chloride salt by electrolysis.

ETCHING – A condition created by aggressive water selectively leaching or dissolved out of a plaster matrix.

FILTER – A device allowing “cleansed” water to pass through on it path back to the pool after trapping particulate matter from the water.

GUNITE – A type of concrete used to form the shell of a pool.

HAIR & LINT BASKET – The basket located in the front section of the pool pump (wet end) where debris collects before entering into the filter.

HOSE BIB – Another term for an outside faucet used as a fill source for a pool.

HYDRATION – Moisture entrapped within the plaster produces a cloud like or streaked look. This condition is highlighted by the refraction of the sun light during various times of the day.

HYPOCHLOROUS ACID – The free state of chlorine that actually destroys the bacteria and other organic wastes.

IONIZATION – The splitting or dissociation (separation) of molecules into negatively or positively charged ions, such as copper and/or silver.

LITHIUM HYPOCHLORITE – Quick dissolving…leaves no residue. 35% available chlorine.

MAGNESIUM – A dissolved mineral in swimming pool water. Contributes to water hardness and turbidity.

MAIN DRAIN - A fixed device located at the bottom of the pool and/or spa. The purpose is to circulate water from the deep water of the pool on the suction side. This allows for better mixing of pool chemicals.

MOTOR – The rear end of an electrical pump. The motor rotates an impeller that moves water back and forth from the pool/spa and the pool equipment.

MOTTLING – This word is improperly used to describe unexplainable phenomenon. Undesirable gray cloud like discolorations on pool surfaces usually originate from a hydration problem or from fallout of metals. The metals originate from source water, metallic algaecides, excessive water velocity through heaters, or the stripping of metals from the system by high oxidizer levels, or aggressive water.

MURIATIC ACID – An acid used to reduce pH and alkalinity. Also used to remove stain and scale.

OTO – A reagent used with your test kit in determining the amount of chlorine in the water.

P-TRAP – The term for the location where the backwash line from the pool filter connects to the sewer system. Typically this location is in front of the house (generally in the flower bed).

pH – pH is an expression of the basic or acid condition of a liquid (water). The pH may range from 0 – 14, where 0 is most acid, 14 most basic, and 7 is neutral. The pH of the eye fluids is 7.4.

PHENOL RED – A reagent used with your test kit in determining the pH of pool water.
PLASTER – The interior finish that covers the gunite structure, waterproofs the shell, and provides the aesthetically pleasing appearance of the pool. The plaster if composed of natural materials that have certain inherent characteristics – a certain amount of shading or color variation.

POOL SWEEP – A device that aids in the cleaning of the pool on a regular basis. There are several types: suction, pressure, auxiliary pump on pressure side, etc.

PPM – Parts per million or pounds per million. The term used to express quantity of a substance in water.

PRECIPITATE – (1) An insoluble, finely divided substance that is a product of a chemical reaction within a liquid. (2) The separation from solution of an insoluble substance.

PRECIPITATION – The chemical transformation of a substance in solution into an insoluble form (precipitate).

PUMP – A piece of equipment that moves water back and forth from the pool to the pool equipment.

RETURN MANIFOLD – A group of pipes and valves that control the flow of water to the pool and/or spa.

SCALE – Mainly composed of calcium carbonate. Shows up as white or dark streaks in the plaster. Caused by minerals precipitating and adhering to the plaster. Discoloration is caused by trapping dirt in the calcium deposit.

SEQUESTERING AGENT - A chemical complexing (forming or joining together) of metallic ions (such as iron) with certain organic or inorganic compounds. Sequestering agent aids in the prevention of the precipitation of metals. Also see CHELATION.

SKIMMER – A fixed device located in the beam/side of the pool. The purpose is to circulate water and remove debris from the surface of the pool on the suction side.

SKIMMER WEIR – The door that is located in the mouth of the skimmer. When the pool system shuts off, the door floats up keeping the debris in the skimmer.

SODIUM DICHLOR (DI-CHLOR) – Quick dissolving granular. There is an available chlorine level of 62%, cyanuric level of 57.3% and a pH level of 6.0.

SPOT ETCHING – A condition caused by the abuse of low pH sanitizers. This process is created when the gaseous vapors build up during pump down time or from floaters banging against the side of pools as they circulate. Initially appears as small spots on horizontal surfaces in the shallowest areas of a pool.

STABILIZER – A chemical when used properly is a very efficient control of chlorine. Inhibits the ultra violet rays of the sun from destroying the chlorine.
Cyanuric acid is normally used as a stabilizer in swimming pool water.

STAINS – Discolorations of a swimming pool surface caused by metal in the water. This condition is created by out of balance water, improper use of algaecides, impingement, and source water. Discolorations can be avoided by the proper water balance, the use of testable sequestering agents and a sequest test kit.

SUCTION MANIFOLD – A group of pipes and valves that control the flow of water from the pool and/or spa.

SUPER CHLORINATION OR SHOCK TREATMENT – Approximately 5 times normal chlorine dosage usually employed during summer swimming months and/or heavier than normal bathing loads on a weekly basis.

TRICHLOR (TRI-CHLOR) – A type of tablet used in an automatic chlorinator. There is an available chlorine level of 89% - 90%, cyanuric level of 54.2% and a pH level of 2.7 – 2.9. The solubility of trichlor triples when the water temperature rises from 77 to 90 Degrees Fahrenheit.

TURBIDITY – Small suspended particles in the water in high amounts will cause cloudiness.

WET END – The front end of a pump that water passes through. The hair and lint basket is located in this section of the pump.