Water that has a pH of 7.4 to 7.6, a total alkalinity of 80 parts per million (ppm) to 140 ppm, calcium hardness of 200 ppm to 400 ppm, and a TDS of less than 2,500 ppm. The water is said to be "in balance" when the water is within these parameters.
(also called coagulant or flocculent) 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.
(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.
A cover that is secured around the perimeter of a pool, spa or hot tub that provides a barrier to bathers and debris when the pool, spa or hot tub is closed for the season.
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.