E-H

Effluent - The water that flows out of a pump, filter or heater, usually on its way back to the pool or spa.

Elbow - A plumbing fitting shaped at a 90 degree or a 45 degree angle usually made of metal, PVC or some other plastic.

Electrolysis - An electrochemical reaction causing a black stain normally found around metal fixtures or on the plaster. It is caused by two dissimilar metals being plumbed together or from an improper electrical grounding of pool equipment or lights. Electrolysis also means the decomposition of water and other inorganic compounds in aqueous solution by means of electricity. Chlorine generators use this principle to produce chlorine from salt in the water.

EPA - Abbreviation for the federal Environmental Protection Agency.

Escutcheon Plate - An ornamental shield, flange or border used around a pie, plumbing fitting, grab rail or light.

F

Fiberglass - Finespun filaments of glass which are available in a rope or mat form. When used in a process with polyester resins, catalysts and hardeners, can be formed or molded into pools, spas and related shapes.

Filter - A device that removes undissolved or suspended particles from water by recirculating the water through a porous substance (a filter medium or element). The three types of filters used in pools and spas are sand, cartridge and D.E. (diatomaceous earth).

Filter Aid - A chemical compound added to the water or to the filter that allows the existing filter to become more efficient. Examples are alum, water clarifiers and D.E. (diatomaceous earth).

Filter Area - The total surface area of the filter medium that is exposed to the flow of water from the pump, expressed in square feet. Examples are: a 36 sq.ft. (also 36 ft2) D.E. filter and a 100 sq.ft. (slao 100 ft2) cartridge filter.

Filter Cartridge - A replaceable porous element made of paper or polyester used as the filter medium in cartridge filters.

Filter Cycle - The operating time between cleaning or backwashing cycles of a filter. Also the amount of time the filter has water flowing through it each day expressed in hours.

Filter Element - A device within a filter tank designed to trap suspended solids as water flows through it from the pool or spa.

Filter Medium - The material used in the filter to trap suspended dirt particles as the water is flowing through it. The polyester or paper used in making a cartridge filter element. The sand used in a sand filter. The D.E. (diatomaceous earth) used in a D.E. filter.

Filter Powder - A common name for diatomaceous earth (D.E.), used as the filter medium in a diatomaceous earth filter.

Filter Rock - Graded, rounded rock and/or gravel used to support the filter medium. Usually used with rapid-rate sand filters.

Filter Septum - That portion of the filter element consisting of cloth, wire screen or other porous material on which the filter medium or filter aid is deposited. The nylon grid on a D.E. filter is the septum.

Filter, Sand - A type of filter media composed of hard, sharp silica, quartz or similar particles with proper grading for size and uniformity. The most common grade used is No. 20 in sand filters.

Filtration Rate - The rate at which the water is traveling through the filter, expressed in U.S. gallons per minute (gpm) per square foot of filter area.

Fireman's Switch - A mechanical switch located inside the time clock, which opens a circuit and shuts off the heater 10 or 15 minutes prior to shutting off the water circulation pump, allowing the heater to cool down. This helps reduce lime buildup in the heat exchanger.

Floc (See flocculation) - The clump or tuft formed when suspended particles combine with a flocculating agent.

Flocculating Agent - Also flocculant - A chemical substance or compound that promotes the combination, agglomeration, aggregation or coagulation of suspended particles in the water.

Flocculation - The combination, agglomeration, aggregation or coagulation of suspended particles in such a way that they form small clumps or tufts (called floc).

Flow Rate - The quantity of water flowing past a designated point within a specified time, such as the number of gallons flowing past a point in 1 minute - abbreviated as gpm.

Foam - A froth of bubbles on the surface of the water. Usually comes from soap, oil, deodorant, hair spray, suntan oil, etc., that is shed into the water as swimmers enter.

Free Available Chlorine - The amount of free chlorine in the pool or spa water that is available to sanitize or disinfect the water. Sometimes called residual or available chlorine.

G

Gelcoat - A colored, polyester-resin material applied to the surface of a molded part. The gelcoat hardens to a smooth, durable form and becomes an integral part of the laminate. Fiberglass pools and spas have gelcoat finishes.

GPD - An abbreviation for gallons per day.

GPH - An abbreviation for gallons per hour.

GPM - An abbreviation for gallons per minute.

Grab Rail - Also called hand rail - A tubular steel or plastic device that can be gripped by swimmers or bathers for the purpose of steadying themselves. Usually located near the steps in the pool.

Green Hair - A condition caused by too much copper in the pool water. Green hair is not caused by chlorine. The copper may get into the water by the bad practice of placing trichlor tabs in the skimmer. This acidic product will cause low-pH water, which in turn will dis- solve metals in the equipment. The dissolved metal (usually copper) then stains hair, fingernails and, eventually, pool walls. It can also be caused by keeping the pH too low or misusing acid.

Ground Fault Circuit Interrupter - Also called a GFCI - A device intended to protect people. It interrupts (de-energizes) the electrical circuit whenever it detects the presence of excess electrical current going to ground (usually 1/40th of a second and 5/1000th of an ampere).

Gunite - A mixture of cement and sand sprayed onto contoured and supported surfaces to build a pool. Gunite is mixed and pumped to the site dry, and water is added at the point of application. Plaster is usually applied over the gunite.

Gutter - An overflow trough at the edge of the pool through which floating debris, oil and other "lighter-than-water" things flow. Pools with gutters usually do not have skimmers.

H

Halogens - The chemical elements either individually or collectively that constitute Group VIIB of the Periodic Table of Elements: fluorine, chlorine, bromine, iodine and astatine. Of these, only chlorine and bromine are used as disinfectants and sanitizers in pools and spas.

Hand Rail - A tubular steel or plastic device that can be gripped by swimmers or bathers for the purpose of steadying themselves. Usually located near the steps in the pool.

Hand Skimmer - A screen attached to a frame which is then attached to a telepole used to remove large floating debris, such as leaves and bugs, from the water's surface.

Hardness - The amount of calcium and magnesium dissolved in the water. "Water" or "total" hardness refers to the total magnesium and calcium dissolved in the water. Calcium hardness refers to just the calcium. Measured by a test kit and expressed as ppm. The proper range is 200 to 400 ppm.

Heat Exchanger - A device located inside the heater providing for the transfer of heat from the heat source to the water. This is usually a series of metallic tubes with fins located just above the flames.

Heater - A fossil-fueled, electric or solar device used to heat the water of a pool, spa or hot tub.

Herbicide - A chemical compound used to kill or control plant growth or algae. Simazine is a common pool herbicide.

Horsepower - The work done per unit of time. 1 horsepower equals 33,000 foot-pounds of work per minute or approximately 746 watts. Motors for pumps are rated in horsepower.

Hot Tub - A spa constructed of wood with the sides and bottom formed separately and joined together by hoops, bands or rods.

Hydrochloric Acid - Also called muriatic acid - A very strong acid used in pools to lower the pH and total alkalinity. It can also be used for various cleaning needs. Used in "acid washing" a pool. Use extreme care in handling.

Hydrogen - The lightest chemical element. A component of water, and a frequent product of many chemical reactions. pH is a measure of hydrogen in its ionic form in water.

Hydrogen Ion - The positively charged nucleus of hydrogen atom. The relative degree of acid or base of a solution (called pH) is a measure of hydrogen ions.

Hydrogen Peroxide - An unstable, colorless, heavy liquid used as a bleach in industry and as an antiseptic in households. It is used as an oxidizing agent in pools and spas. May also be used to de- chlorinate pool or spa water.

Hydrojet - A fitting in the pool or spa on the water return line from the equipment that blends or mixes air and water, creating a high- velocity, turbulent stream of air-enriched water.

Hypobromous Acid - The most powerful disinfecting form of bromine in water. Sometimes called the killing form of bromine.

Hypochlorite - The name given to a family of chlorine- containing compounds, including calcium hypochlorite, sodium hypochlorite and lithium hypochlorite, that are used as disinfectants and sanitizers in pool and spa water.

Hypochlorous Acid - The most powerful disinfecting form of chlorine in water. Sometimes called the killing form of chlorine.

Back to Glossary