The interior pool wall surfaces. May be plaster, vinyl, fiberglass, and various other materials.
Water Balance
Water that has a pH of 7.4 to 7.6, a total alkalinity of 80 to 140 ppm, Calcium Hardness of 200 to 400 ppm, and a TDS of less than 2500 ppm. The water is said to be "in balance" when the water is within these parameters.
Water Clarifier
(also called coagulant or flocculant) A chemical compound used to gather (coagulate or agglomerate), or to precipitate suspended particles so they may be removed by vacuuming or filtration. There are two types: inorganic salts of aluminum (alum) and other metals or water-soluble organic polyelectrolytes.
Water Hammer
The shock wave or series of waves produced by the abrupt acceleration or deceleration of water flow through a pipe, caused by inertia.
Waterborne Disease
A disease caused by a bacteria or organism able to live in or be carried by water. A disease transmitted through the ingestion of contaminated water. Water acts as a passive carrier of the infectious agent.
Waterline
The height to which the water is filled in the pool or spa. This is usually in the middle of skimmer openings, the center of the tile pattern or to the overflow if so constructed.
Weight Per Gallon
Water weighs 8.34 pounds per gallon at 77° F.
Weir
(also called skimmer weir) Part of a skimmer that adjusts automatically to small changes in water level to assure a continuous flow of water to the skimmer. The small floating "door" on the side of the skimmer that faces the water over which water flows on its way to the skimmer.
Winterizing
The procedure for preparing the pool or spa for freezing weather. Includes chemical treatment and physical treatment to protect equipment and vessel – draining, anti-freeze, drain plugs, etc.
