I-M

Impeller - The rotating member of a pump. The part of the pump that moves the water.

Influent - The water entering the pump, the filter or other equipment of space. Water going into the pump is called in influent, while water leaving the pump is called the effluent.

Inlet - A fitting in the pool or spa on the water return line from the equipment that water returns to the pool. Usually the last thing on the return line.

Ionizer - A water-sanitation device that uses electricity to generate metal ions, which are dispersed in the water. It works by passing a low-voltage DC current through a set of metallic (usually copper and silver) electrodes placed in line with the circulation equipment. The copper is an algaecide, while the silver is a bactericide. Does not remove swimmer waste.

Iron - Iron in water causes the water to be brown- or green-colored. Can be controlled by the addition of a sequestering agent or a chelating agent. Water can be tested with an iron test kit.

Isocyanurates - Also called stabilized chlorine - A family of chlorine pool sanitizers that contain conditioner (cyanuric acid or isocyanuris acid) to protect the chlorine from the de- grading UV rays in sunlight. The most com- mon types are sodium dichlor and trichlor. The granular form is dichlor, which is fast- dissolving and can be used for regular chlorination or super chlorination by broad- casing into the pool or spa. Tablet or stick form is trichlot (which is usually used in a chlorine feeder - either the floating type or the in-line erosion type) used for regular chlorination only.

J

Jacuzzi® - A brand name and registered trademark for a specific line of spas and whirlpools.

L

Ladder - A structure for climbing up or down; consists of two parallel sides joined by a series of crosspieces that serve as footrests. It is used for getting in and out of the pool. A double-access ladder straddles the pool wall of an above-ground pool. An in-pool ladder is located in the pool only.

Leaf Bagger - A device that attaches to a telepole and a garden hose. Pressure from the garden hose creates a suction by which leaves and large debris are sucked into a large mesh bag.

Light Niche - The area in a pool or spa that houses the underwater light.

Liner - Also called vinyl line - The vinyl membrane that acts as the container to hold or contain the water.

Liquid Acid - (31.45% hydrochloric acid) - also called muriatic acid - It is used for lowering pH, total alkalinity and for various cleaning needs. It is also used for acid washing.

Liquid Chlorine - A sodium hypochlorite solution. Usually provides 10 to 12% available chlorine; has a pH of 13 and requires that small amounts of acid be added to the pool to neutralize the high pH. Good for regular chlorination and super chlorination.

Lithium Hypochlorite - A dry, granular chlorinating compound with an available chlorine content of 35%. It is rapid-dissolving and can be used to super chlorinate vinyl-liner pools, painted pools or fiberglass pools as well as spas and hot tubs.

M

Magnesium Hardness - A measure of the amount of magnesium dissolved in the water. It is part of total or water hardness. It also causes scale if levels are too high.

Main Drain - This term usually refers to a plumbing fit- ting installed on the suction side of the pump in pools, spas and hot tubs. Sometimes called the drain and is located in the deepest part of the pool, spa or hot tub. It is not a drain, such as a drain on a kitchen sink. Main drains do not allow the water to drain to waste but rather connect to the pump for circulation and filtration.

Make-Up Water - This is sometimes called "tap" or "refill" water. It is the water used to replace water lost to evaporation, splash-out, leaks or swimmer drag-out in the pool.

Manifold - The branch pipe arrangement that connects several input pipes into one chamber or one chamber into several output pipes. A filter manifold connects several input pipes from the filter septa back into one common pipe.

Marcite - Originally a brand name for a white plaster finish coat from 1/8th to 1/2 inch thick applied over the gunite or shotcrete.

Micron - A unit of length equal to 1 millionth of a meter - it is .000394 of an inch. Microns are used to describe the pore size of filter media. Sand filters have openings of 25 to 30 microns; cartridge filters have openings of 8 to 10 microns; and D.E. (diatomaceous earth) filters have openings of 1 to 5 microns. Humans, without magnification, can see objects 35 microns or larger. A granule of table salt is between 90 to 110 microns.

Mineral - Any substance that is neither animal or vegetable. It is any class of substances occurring in nature, usually comprising of inorganic substances, such as quartz or feldspar, of definite chemical composition and definite crystal structure. It sometimes includes rocks formed by these substances. Ground water dissolves these rock substances, and the dissolved minerals are present in tap water. Depending on the kinds of rocks the water comes in contact with, the minerals dissolved in the water may be just a few or they may be many. Water hardness is mostly comprised of these minerals.

Multiport Valve - Also called a rotary-type backwash valve - This valve replaces as many as 6 regular gate valves. Water from the pump can be diverted for various functions by merely turning the valve handle. The water may be sent to waste, used for backwashing, bypassing the filter for maximum circulation, for normal filtration, filtering to waste (rinse), or the valve may be closed to not pass water. The pump must be off before changing a valve setting.

Muriatic Acid - (31.45% hydrochloric acid) - Also called liquid acid - An acid used to reduce the pH and alkalinity levels in pool water. It is also used in acid washing, a process that removes stains and scale from pool plaster.

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