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.
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.
HEAT PUMP A
refrigeration compressor, usually electrically driven, that is operated in
reverse. To obtain heat, the evaporator side (cooling coil) is exposed to water,
air or ground. The coil takes the heat from this source and transfers it to the
condenser coil where it discharges the heat to the pool or spa to be heated.
HEATER A fossil-fueled,
electric or solar device used to heat the water of a pool, spa or hot tub.
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.
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.
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.
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.
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.
(also see biguanide)
HYDRO-JET 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.
The most powerful disinfecting form of bromine in water. Sometimes called the
killing form of bromine.
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.
The most powerful disinfecting form of chlorine in water. Sometimes called the
killing form of chlorine.