FROG Water Care Experts Glossary of terms

Type of filter that uses sand to clean the water.

A general term for a substance used as a disinfectant to kill bacteria and algae and oxidize organic contaminants. Generic names include Bromine, Biguanide and Chlorine.

Mineral deposits that form on pool or spa surfaces and equipment due to excessive calcium in the water when the pH level is high. Scale may appear as gray, white or dark streaks on the plaster, fiberglass or vinyl. It may also appear as a hard crust around the tile.

The extraneous or foreign matter which rises to the surface of the water and forms a layer or a film there. It can also be residue deposited on the tile or walls of the pool or spa. Sources of scum include soap, oil, deodorant, hair spray, suntan lotions and others.

The solid material settled out from the water.

A chemical that bonds with metals so that they can't cause staining or discoloration. See also Chelating Agent.

An oxidizer that burns off the organic waste that causes cloudiness and algae. It's a generic term for a chemical used to oxidize organic waste.

The practice of adding a significant amount of an oxidizing chemical (usually non-chlorine oxidizers, such as sodium persulfate or potassium peroxymonosulfate) to the water to control ammonia, nitrogen compounds or swimmer waste.

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

Soil particles having diameters between 0.004 and 0.062 millimeters. Sometimes they may be too small to be trapped by the circulation system. In those cases, a clarifier or an alum product may be needed.

A system that uses silver ions to kill water bacteria.

A chemical substance used in swimming pools and spas as an herbicide or algaecide. Mainly used for killing black algae.

The white, box-like compartment on the side of the pool that automatically skims the top few inches of water, removing debris and oily films. Contains a removable basket that needs to be periodically cleared of debris.

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 the water flows on its way to the skimmer. The weir also prevents debris from floating back into the pool when the pump shuts off.

A manually controlled valve with two settings used to direct pool water flow.

A method of lowering total alkalinity by pouring pH decreaser in one concentrated spot and turning off the filter.

Water or a liquid containing a high concentration of suspended solids. Diatomaceous earth (D.E.) is usually added to the filter as a slurry by mixing a small amount of D.E. in a bucket of water and then pouring the slurry into the skimmer with the filter on.

See Sodium Carbonate.

Baking Soda or Bicarb. The alkaline salt compound used to raise Total Alkalinity. Not to be used for increasing pH. Also called Bicarb or Bicarbonate of Soda.

Dry Acid - also called pH Down. Used to decrease the pH and/or Total Alkalinity of water.

A salt of bromine. It is used to establish a bromine "bank" in pool and spa water prior to beginning the use of bromine tablets.

Soda Ash. Used to increase the pH of water. Also called ph Up.

Also called Alkalinity Up or pH Stabilizer. Used to raise total alkalinity.

Otherwise known as common household bleach.

Active ingredient and chemical name of a non-chlorine shock treatment or non-chlorine oxidizer. Does not kill bacteria or algae but it will oxidize or control ammonia, nitrogen and swimmer waste. Does not increase chlorine or bromine levels the way the superchlorination does, so water may be entered 15 minutes after addition. It will not reactivate bromine.

A chemical mixture of equal parts soda ash and sodium bicarbonate used to increase pH and total alkalinity in pool and spa water. It has a pH of 10.1.

A chemical used to neutralize or de-chlorinate pool and spa water.

A chemical used to neutralize or de-chlorinate pool and spa water.

Water low in calcium and magnesium mineral content (water hardness) - usually less than 100 ppm. Also, water that has gone through a water softener. Pools and spas should not be filled with soft water from a softener. Water with less than 100 ppm of hardness should be increased to a minimum of 150 to 200 ppm using calcium chloride.

A cover that, when placed on the water's surface of a pool or spa, increases the water temperature by absorption and transmission of solar radiation; reduces evaporation and prevents wind-born debris from entering the water.

Accessory tubes through which water is warmed by the sun and returned to the pool.

Also called "tap" water. It is the water used to fill or refill the pool or spa.

Chlorine that contains Cyanuric Acid to protect the chlorine from the degrading UV rays in sunlight. Most common types are sodium dichlor and trichlor.

A discoloration or a colored deposit on the walls or bottom of a swimming pool or spa. Most often, stains are metals such as iron, copper and manganese. They may appear as green, gray, brown or black and may even discolor the water. Sometimes a sequestering or chelating agent will remove them. If not, usually an acid wash is necessary to remove them from the walls and bottom. The metals get into the water because the pH was too low or someone has added a low-pH chemical directly into the circulation system. Stains are sometimes confused with scale.

Also called a sequestering or chelating agent. A chemical that will combine with dissolved metals in the water to prevent the metals from coming out of solution (precipitating or causing stains). May also be a chemical that removes dissolved metals from water.

A basket in front of the pump that keeps fine debris from reaching the pump's impeller area. Must be cleaned periodically. Sometimes called a "hair and lint trap".

The addition of sanitizers in larger amounts than normal (5-10X dosage) to burn out organics, chloramines, etc. See Shock.

A plastic, flat mesh net skimmer used to scoop up and remove floating debris.

A soluble chemical compound that reduces the surface tension between two liquids. It is used in many detergents and soapy cleaning compounds.

Insoluble solid particles that either float on the surface or are in suspension in the water, causing turbidity, or a cloudy condition. They may be held in suspension by agitation or flow. They may be removed by filtration, but if the particles are too small, they may not be trapped by the filter. In these cases, a clarifier or alum may be needed to remove them.