Algae: Algae are living organisms that need water, sunlight, phosphates, nitrogen, and carbon dioxide to grow. Typically algae are green, but they can be yellow or black. (Pink algae is actually a form of bacteria.) Algae can grow on the surfaces of your pool or bloom in suspension. Their spores can enter the pool by way of wind, rain, contaminated swimsuits or equipment.
Algaecide: A product that kills algae. Algaecides perform best as a backup to a routine sanitation program.
Algaestat: As opposed to an algaecide, an algaestat retards and prevents the growth and development of algae.
Alkalinity: A measure of the pH buffering capacity, or the water’s resistance to change pH.
Ammonia: A nitrogen-containing compound introduced into the water by swimmers as waste (perspiration or urine). It quickly combines with chlorine to form bad-smelling chloramines, which are harmful to our health.
Backwash: Thoroughly cleaning a sand filter by reversing the flow of water through it so the dirt and rinse water run out, away from the pool.
Bromine: A member of the halogen family commonly used as a sanitizer or disinfectant to destroy bacteria and algae in spas. It is resistant to heat and rapid pH fluctuations.
Calcium hardness: The calcium content of the water. If the level is too low, the water may be corrosive. If it is too high, the water may form scale.
Carbon dioxide: A gas which, when is present in the water, provides necessary nutrients for algae to photosynthesize and reproduce in the presence of sunlight.
Cartridge: A porous element made of paper or polyester which is used as a filter medium in a cartridge filter.
Cavitation: A general term used to describe the behavior of voids or bubbles in a liquid. Cavitation is divided into two classes of behavior: inertial and non-inertial. Inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Such cavitation often occurs in pumps and impellers. Non-inertial cavitation is the process where a bubble in a fluid is forced to oscillate in size or shape due to some form of energy input, such as an acoustic field. Such cavitation can be observed in pumps.
Chitin: A naturally occurring polymer found in the shells of crabs and lobsters, which is contained in the product Sea Klear. Chitin acts as a coagulant and flocculant for oils, metals, and organic materials.
Chloramines: Undesirable, smelly compounds formed when insufficient levels of free chlorine react with ammonia- and nitrogen-containing compounds, Chloramines are a threat to human health and can be destroyed by shock treatments or super chlorination.
Chlorine: A compound used in swimming pools in the form of liquid, granular and tablets. When added to the water it acts as an oxidizer, sanitizer, and disinfectant.
Chlorine free available: The amount of free chlorine that is available to sanitize or disinfect the water.
Circulation system: The circuit of plumbing which continuously carries the water out of the pool, through the pump and filter, then returns it to the pool.
Combined chlorine: The measure of chlorine that has attached itself to molecules or organisms, typically ammonia or nitrogen compounds.
Chlorine demand: The amount of chlorine necessary to oxidize all organic matter (bacteria, algae, chloramines, ammonia, etc.) in the water.
Conditioner: Also called cyanuric acid (CYA) or stabilizer. It protects chlorine in the water against the effect of the sun’s UV rays.
Chlorinator: A device that allows the safe, controlled introduction of chlorine into the water.
Clarifier: Used to coagulate, clump, or precipitate suspended particles in the water so they can be removed by vacuuming or filtration.
Diatomaceous earth: A filter medium, which is the fossilized remains of the ancient plankton, diatom.
Dichloro-s-triazinetrione: A chemical compound that serves as an oxidizer, bactericide, algaecide, and cleaning agent that reacts with water to form hydroclorous acid.
DPD: A method of testing chlorine levels in the pool. Unlike OTO, DPD testing allows the determination of total and free chlorine levels which, through substraction, gives us the combined levels.
Enzymes: Proteins designed to break down and digest oils in the pool or spa.
Filter medium: The material used to trap suspended dirt particles as water flows through the filter.
Filtration rate: The rate of water pumped through the filter, in gallons per minute (gpm).
Flow rate: The quantity of water flowing past a specific point in a specified time (the number of gallons flowing through the filter per hour).
Heater: A device used to heat the water.
Heat exchanger: A set of 8 to 10 ribbed copper tubes that absorb the heat produced below it and transfer it to the water cycling through its tubes.
Hydrostatic pressure: A force involving built-up ground water that creates upward pressure beneath the pool shell.
Iron: A natural element that can cause water to become clear, brown, or green and can result in the staining of pool surfaces.
Lithium hypochlorite: A quick dissolving granular chlorine compound used for superchlorination in vinyl-liner, fiberglass, painted, and gunite pools.
Muratic acid: The liquid dilution of hydrochloric acid used to lower pH and alkalinity. It is extremely caustic and corrosive.
Non-chlorine shock: A granular form of potassium permonosulfate used to oxidize materials such as microorganisms, contaminants, and chloramines.
Oxidation: The burning up of organic wastes and compounds in the pool water.
pH: The scale of relative acidity and alkalinity expressed in logarithmic numbers from 0-14 with 7.0 being neutral.
Phosphates: Food for algae. Found in fertilizer and lawn care products, they can be carried for miles in the air.
Potassium permonosulfate: See non-chlorine shock.
Pressure gauge: A device indicating pressure in the filter system. It provides a determination on how the system is operating, and informs us when service is required.
Residual: Usually refers to free available chlorine levels remaining in the pool after initial treatment or activity with contaminants.
Restricted flow: A condition preventing full flow of water. Restriction can occur with full skimmer or strainer baskets, obstructions in the plumbing, dirty filter, etc. Restriction on the suction side creates higher vacuum (or suction), while on the pressure side it creates higher pressure.
Sand filter: A filter tank filled with sand or zeosand. The pump diffuses water over the top of the sand bed, and forces it through the sand and into the laterals on the bottom.
Scale: Usually whitish in color, scale forms on pool surfaces and equipment when the mineral salts are forced out of solution.
Shock: The act of bringing the sanitizer level so high that breakpoint chlorination is reached. When breakpoint is reached, “shock” is sent through the water, tearing apart molecules and slashing through cell walls. It is the ultimate purification.
Stabilizer: CYA or cyanuric acid. It protects chlorine in the water against the effects of the sun’s UV rays.
Super chlorination: Applying 7 to 10 times the amount of chlorine to the pool as an added "boost" for contaminant removal.
TDS (total dissolved solids): A residual of everything that has ever dissolved in your pool water, including suntan lotions, hair care products, body oils and waste, chemicals and environmental debris.
Trichlor-s-triazinetrione: A solid form of chlorine, usually sticks or tablets.