The practice of adding significant amounts of an oxidizing chemical to water to destroy ammonia or nitrogenous and organic contaminants in water.

A mixture of cement and sand applied onto contoured and supported surfaces to build a pool or spa. Shotcrete is premixed and pumped wet to the construction site.

Part of a skimmer which adjusts automatically to small changes in water level to assure a continuous flow of water to the skimmer.

A white powder used to raise pH of the water.

A white powder used to raise the total alkalinity in water.

A granule used to lower pH and/or the total alkalinity in water.

Also known as Sodium dichloro-s-triazinetrione. An organic chlorine, granular in form, approximately 62 percent chlorine; in the dehydrate form, approximately 56 percent chlorine. It contains 58.7 percent stabilizer by weight and has a pH of 6.0. See also Organic Chlorine.

A clear liquid form of an inorganic chlorine compound obtainable in concentrations of 5 to 16 percent available chlorine.

See Cyanuric acid.

The aperture of fitting through which the water under negative pressure is drawn from the pool or spa.

That piping which is referred to as influent.

The practice of adding a sufficient amount of chlorinating compound to water to destroy chlorine demand compounds and any combined chlorine which may be present. Generally the level of chlorine added is 10 times the level of combined chlorine in the water. (See Breakpoint chlorination.)

This term encompasses perimeter-type overflows, surface skimmers, and surface water collection systems of various design and manufacture. See Skimmer.

The ability of capacity of water to resist change in pH; also known as the buffering capacity of water. Measured with a test kit and expressed as ppm.

The sum of both the free available and combined chlorines.