Calcium Hardness (CH)
The amount of dissolved calcium in water. Ideal range 200-400 ppm depending on surface type. Determined by use of a test kit for that purpose. If the calcium hardness level is too low, the water may be corrosive. If the calcium hardness level is too high, the water may have a tendency to form scale.
Cartridge
A disposable porous element made of paper or polyester which is used as the filter medium in cartridge filters.
Cartridge Filter
A water filter that uses a replaceable porous element made of paper or polyester.
Chelating Agent (Also a Sequestering Agent)
A chemical that will combine with dissolved metals in the water to prevent the metals from coming out of solution and so avoiding discoloration of the water or stains.
Chemical Feeder
A device that dispenses chemicals into the pool water at a predetermined rate. Some provide chlorine or bromine while others add pH-adjusting chemicals.
Chloramines
Undesirable smelly compounds formed when insufficient levels of free available chlorine react with ammonia and other nitrogen containing compounds (swimmer waste, sweat, urine, suntan lotions, etc.). Chloramines are very poor sanitizers and can be destroyed by shock treatment or super chlorination.
Chlorine
A member of the halogen family of sanitizers. Chlorine is used in swimming pools in the form of liquid, granular or tablet. When added to water it acts as an oxidizer, sanitizer, disinfectant and biocidal agent.
Chlorinator
A device that dispenses chlorinating compounds into pool water in a controlled, gradual manner.
Chlorine Demand
The amount of chlorine addition required before a free chlorine residual can be maintained.
Chlorine Residual
The amount of chlorine left to kill new bacteria entering the pool. Also, the amount of chlorine left after chlorine demand has been satisfied.
Clarifier
A chemical compound used to coagulate, clump or precipitate suspended micro particles so they can be removed by vacuuming or filtration to promote clear, clean pool water.
Clarity
The degree or measure of the transparency of water.
Contaminants
The general name for any micro particle or organism which reduces water clarity, quality or presents health hazards. Filtering, oxidizing and sanitizing are necessary to destroy the contaminants.
Copper algaecide
A chemical compound that contains the element copper. Most copper algaecides contain ingredients that prevent the copper from staining but do not affect copper's ability to kill algae.
Corrosion
The effects of an acidic pool environment; one in which the pH and/or alkalinity are very low. Corrosion in the form of etching, pitting or erosion of pool equipment and surfaces is the result.
Combined Chlorine (Chloramines)
Chlorine-ammonia compounds that can cause chlorine odor and eye irritation. This compound is a poor sanitizer for pool water applications.
Cover, Winter
A cover that is secured around the edges of a pool when the pool is closed for the season.
Cyanuric Acid (Also conditioner and stabilizer)
A granular chemical added to the pool water which provides a shield to chlorine for protection from the sun's UV radiation. It is also found in dichlor/trichlor products.