Used to lower a pool's pH (toward a more acidic condition) or to lower total alkalinity levels, it's available as a liquid (muriatic acid) or dry (sodium bisulfate).
AIR-RELIEF VALVE:
A manually operated valve located on the top of a filter tank for relieving the pressure inside the filter or for removing the air trapped inside the filter (bleeding the filter).
ALGAE:
This living, breathing organism may form on your pool surfaces or it may bloom in suspension. With over 20,000 different species, algae is usually green, but it may also be yellow (mustard algae), black, blue-green, or any shade in between. It may form separate spots or seem to grow in sheets.
ALGAECIDE:
Algaecides kill algae and are best used as a backup to a routine sanitation program. They also help to kill airborne spores as they blow into the pool.
ALKALINITY:
Also called Total Alkalinity. A measure of the water's resistance to change in pH. It is composed of the hydroxides, carbonates and bicarbonates in the water.
AUTOMATIC POOL CLEANER:
A device which agitates or vacuums debris from the walls and floor of the pool.
AVAILABLE CHLORINE:
The amount of free chlorine that is available to sanitizes and disinfect the water. It is also known as Free Available Chlorine.
Thoroughly cleans the filter medium and/or elements.
BACTERIA:
These micro-organisms may live in pool water and cause disease.
BALANCED WATER:
When all of your pool chemical parameters – pH, totally alkalinity. Calcium hardness and temperature – are where they should be.
BLEACHING OUT:
At or above 10ppm a DPD test kit often indicates zero chlorine because the color in the reagent is being destroyed. If you observe an initial pink color which then rapidly fades, you have too much chlorine in the water.
BREAKPOINT CHLORINATION:
When you shock a pool, the goal is to reach a high enough level of free chlorine to break apart all molecular bonds; specifically the combined chlorine molecules, ammonia or nitrogen compounds and to completely oxidize all organic matter. Adding enough chlorine to achieve this is breakpoint chlorination. Chlorine added after that point will be free available chlorine.
BROMINATOR:
A mechanical or electrical device for dispensing bromine at a controlled rate. It is most commonly a canister or floater filled with bromine tablets
BROMINE:
This halogen is usually used as a spa sanitizer.
BUFFER:
A base that's added to your pool to increase alkalinity and buffering capacity, which is your pool's resistance to pH change.
BYPASS:
An arrangement of pipes and valves which adjust the flow of water. It may be passed around the filter rather than through it, and usually refers to circulating the water without filtration.
These scaly crystalline deposits may form on your pool surfaces, equipment, or pipes if pool water isn't properly balanced.
CALCIUM CHLORIDE:
The flaked calcium salt raises your pool's calcium hardness levels.
CALCIUM HARDNESS:
A titration test is used to determine levels of the mineral calcium dissolved in the pool water.
CALCIUM HYPOCHLORITE:
A compound of chlorine and calcium used as a disinfectant, sanitizer, and oxidizer in swimming pool water.
CARTRIDGE FILTER:
A type of filter that uses a replaceable porous element made of paper or polyester.
CHECK VALVE:
A one way flow device.
CHLORAMINES:
Undesirable, foul smelling compounds that require shocking the pool water to get rid of.
CHLORINE:
Available as a gas, liquid, granular, or tablet compound, it's added to pool water as an oxidizer, sanitizer and disinfectant.
CHLORINE, COMBINED:
The measure of chlorine which has attached itself to other molecules or organisms, typically ammonia or nitrogen compounds. Most of these compounds are present as unwanted chloramines.
CHLORINE, FREE AVAILABLE:
Free available chlorine is active chlorine and is not combined with any other molecule. A portion of the free available chlorine is present as hypochlorous acid, which reacts to destroy organic material in the pool water.
CHLORINE, TOTAL:
The sum of combined and free available chlorine levels. With a DPD test kit, DPD1 determines free available chlorine and DPD3 shows total chlorine. The difference, if any, is the level of combined chlorine.
CHLORINE DEMAND:
The amount of chlorine necessary to oxidize all organic matter (bacteria, algae, chloramines, ammonia and nitrogen compounds) in the pool water.
CHLORINE GENERATOR:
A miniature chlorine factory.
CHLORINE LOCK:
If the level of cynauric acid (stabilizer) in the water is much over 80ppm, the chlorine becomes trapped and is unable to oxidize effectively. The only way to fix this is to drain some of the water and refill the pool. Be careful when using stabilized chlorine products (dichlor or trichlor) to prevent the level of cynauric acid increasing too much.
CHLORINE NEUTRALISER:
A chemical used to deactivate or destroy chlorine. It is used in better test kits to prevent the bleaching effect of the chlorine and consequently to increase the accuracy of the tests.
CHLORINATOR:
Allows for the safe controlled introduction of chlorine into the water.
CIRCULATION SYSTEM:
This plumbing system continuously carries the water out of the pool, through the pump and filter then returns it to the pool.
CONTAMINANTS:
Any micro-particle or organism which reduces water clarity or quality and may present a health hazard.
COPPER ALGAECIDE:
A chemical compound that kills algae, but won't stain the pool. These are known as chelated copper algaecides.
CORROSION:
The effects of an acidic pool environment, corrosion may appear in the form of etching, pitting, or erosion of pool equipment and surfaces.
COVER, AUTOMATIC:
Solid reinforced vinyl which rolls onto a reel on one end of the pool and attaches on the sides into small aluminum tracks via motor or hand-crank. Provides safety, debris protection, and heat/chemical/water retention.
COVER, HARD TOP:
A cover which rests on the edge or coping of the spa or small pool. Provides a barrier to debris and possibly people, while retaining heat.
COVER, SOLAR:
This cover floats on the surface and uses the sun to warm the water and prevent chemical/heat/water evaporation.
COVER, WINTER:
A barrier to sun and debris, winter covers secure the pool from contamination. Mesh and solid styles are available.
CYANURIC ACID:
This granular chemical protects chlorine from UV radiation, which destroys its sanitizing ability.
Also called anti-foam. A chemical added to the water to destroy the foam. These products do not remove the source of the foaming.
DIATOMACEOUS EARTH (D.E.):
D.E. is a white powder composed of fossilized skeletons of unicellular organisms called diatoms. The skeletons are porous and have microscopic spaces. The powder is added through the skimmer with the pump on and deposits itself on a grid. The powder then becomes the filter medium.
DIATOMACEOUS EARTH (D.E.) FILTER:
A filter designed to use diatomaceous earth (D.E.) as the filter medium.
DICHLOR:
The common name for sodium dichloro isocyanuric acid, a quick dissolving chlorine compound made up of chlorine and cynauric acid. Shock treatment with dichlor is not recommended as it may result in over stabilization and chlorine lock. If dichlor is used, a monthly check of the cynauric acid level is recommended, to prevent over stabilization and chlorine lock.
DISINFECT:
To kill all pathogenic (disease-causing) organisms.
DISINFECTANT:
Chemicals or processes that destroy microorganisms and other contaminants.
DRAIN:
This plumbing fitting is the start of one suction line to the pump and is usually situated at or near the center bottom of the pool.
DRY ACID:
Sodium bisulfate, also known as a pH decreaser, is a granular form of acid used to lower pH and alkalinity in the water. It is safer and less caustic than muriatic acid.
The water used in filling or topping up the swimming pool.
FILTER:
Removes un-dissolved or suspended particles from water by the flow of the water through a porous substance (a filter medium or element). The three main types of filters used in pools are sand filters, cartridge filters and D.E. filters.
FILTER AREA:
The total surface area of the filter medium that is exposed to the flow of water from the pump, expressed in square feet.
FILTER MEDIUM:
The material used in the filter to trap suspended dirt particles as the water flows through it. It is the polyester cartridge filter element in a cartridge filter, the sand in a sand filter and the diatomaceous earth in a D.E. filter.
FILTER SAND:
Sand made up of hard and sharp silica or quartz which have been graded for size and uniformity, and is used as the filter medium in sand filters.
FILTRATION RATE:
The speed at which the water is travelling through the filter. It is expressed in gallons per minute.
FLOCCULANT:
Also called a Flocculating Agent. Virtually the same as a coagulant, it is a chemical substance that clumps suspended particles or algae into a heavy mass, which can be caught by the filter or sinks to the bottom of the pool for vacuuming.
FLOW RATE:
The quantity of water flowing past a specific point in a specified time
A mixture of cement and sand which is sprayed onto the steel reinforced walls and floor of a hole to build a pool. The gunite surfaces are generally marbledusted.
Also called muriatic acid. A very strong acid used in pools to lower the pH or total alkalinity. It can also be used for cleaning an empty pool (acid washing).
The rotating part of a pump that is responsible for the movement of water through the pump.
IRON:
A natural element that can cause the water to become clear brown or green in color and stain pool surfaces. Iron can be controlled by the addition of a suitable sequestering or chelating agent
Also called Langelier Index or Saturation Index, it determines water balance according to the levels of pH, Total Alkalinity, Calcium Hardness and water Temperature. When all the parameters are in balance, the water will neither be corrosive or scaling.
LEAF NET:
Also called a Hand Skimmer, it's a net attached to a frame which is then attached to a pole to remove large floating pollutants such as leaves and insects from the water's surface.
LIQUID CHLORINE:
Chemically, sodium hypochlorite. It usually has 12% to 15% available chlorine and has a pH of 13. It is generally cheap, but difficult and dangerous to handle. It also loses its potency rapidly and is usually only used in large commercial pools.
This usually refers to the drain that is located in the deepest part of the pool.
MAKE-UP WATER:
Also called top up or refill water, it replaces water lost to evaporation, splash-out, leaks and backwashing.
MARBLEDUST:
Also referred to as plaster, this mixture of white cement and white marble dust creates the interior finish over the gunite of a pool. It can be given a color or left white.
MULTIPORT VALVE:
Also called a 6-way valve. Water from the pump can be diverted for various functions by turning the valve handle. The water may: be sent to waste; be used for backwashing; bypass the filter for maximum circulation; filter normally; rinse the filter, or the valve may have all its ports closed. The pump must be off before changing a valve setting.
MURIATIC ACID:
Also called liquid acid or hydrochloric acid, this very strong acid lowers a pool's pH and total alkalinity. It can also be used for cleaning an empty pool (acid washing).
A chemical used to deactivate or destroy chlorine or bromine, it's used in better test kits to increase their accuracy.
NITROGEN:
A gas that causes algae to bloom and disables chlorine. It is introduced into the water by rain and by swimmers. Maintaining proper chlorine levels will prevent nitrogen from becoming a problem. Superchlorination can destroy nitrogen and nitrogenous compounds.
NON-CHLORINE SHOCK:
A granular form of potassium monopersulfate used to oxidize materials such as microorganisms, contaminants (ammonia, nitrogen, swimmer waste) or chloramines.
The burning up or destruction of organic waste and organic compounds in the pool water.
OXIDIZER:
Any compound that removes or destroys organic waste and organic compounds in the water.
OZONATOR:
An electrical device that produces ozone that is introduced into the water as a sanitizer.
OZONE:
A molecule containing three atoms of oxygen. It is known to be a very powerful sanitizer. Ozone-producing equipment creates this molecule by UV radiation or corona discharge.
Indicates the level of acidity or alkalinity of water. A pH of 7.0 is neutral; below 7 is acidic; above 7 is alkaline or basic. The ideal range for pH in swimming pools is 7.0 to 7.6. The pH of our tears is 7.2 to 7.4.
ppm:
The abbreviation for parts per million. It is a method of assigning value to concentrations of chemicals in the water.
PRESSURE GAUGE:
A gauge that indicates the pressure in a closed container such as a sand filter.
PUMP:
A mechanical device which causes water to flow under pressure for the purpose of filtration or circulation.
PUMP CURVE:
Also called a Pump Performance Curve, this graph shows a pump's water flow capacity at any given resistance.
The foreign matter that floats to the water surface and forms a layer or a film. It can also refer to a residue deposited on the tiles or walls of the pool.
SEDIMENT:
The solid material that settles to the floor of the pool.
SEQUESTERING AGENT:
Also called Chelating Agent, this chemical or compound combines with dissolved metals or minerals in the water to prevent them coloring the water or causing stains.
SKIMMER:
A device installed in the wall of a pool that is connected to the suction line of the pump. The suction pulls in water and floating contaminants.
SKIMMER BASKET:
A removable basket or strainer placed in the skimmer to trap large solids from the water before they get to the pump or filter.
SKIMMER NET:
A net attached to a frame attached to a pole that removes large floating pollutants such as leaves and insects from the water's surface.
SKIMMER WEIR:
The small floating door on the side of the skimmer over which water flows on its way to the skimmer. The weir prevents debris from floating back into the pool when the pump is off.
SODA ASH:
Chemically, Sodium Carbonate, this base raises the pH of acidic (below pH 7.0) water.
SODIUM BICARBONATE:
Also called Baking Soda or Bicarb, this base raises Total Alkalinity in pool water with only a slight effect on the pH. Sodium bicarbonate can only raise the pH of the water to 8.5, regardless of the amount used. Care should be taken, however, to avoid adding large quantities at one time.
A device used to measure specific chemical residuals, levels in pool water. Kits usually contain reagents, vials, titrants and color comparators for the tests. The most common tests are: pH, free available chlorine, combined chlorine, total alkalinity, calcium hardness, cyanuric acid and metals.
TIME CLOCK:
Also called a Timer, this electrical device automatically turns the pump on or off at predetermined intervals or times.
TOTAL ALKALINITY:
The total amount of alkaline materials present in the water, usually measured as carbonate alkalinity. It indicates the water's resistance to change in pH. Low total alkalinity causes pH bounce. High total alkalinity causes the pH to constantly rise.
TOTAL CHLORINE:
The total amount of chlorine in the water. It is the sum of free available chlorine and combined chlorine.
TOTAL DISSOLVED SOLIDS:
Also called TDS. A measure of everything that has ever dissolved in the water and all the matter that is in solution. The only way to lower TDS is to drain part of the water and replace it.
TRICHLOR:
A slow-dissolving, tablet or granular stabilized chlorine compound that provides 90% available chlorine. It must be dispensed using a feeder or an in-line chlorinator. Trichlor contains cyanuric acid that prevents the chlorine from being destroyed by the ultraviolet rays of the sun. When using trichlor, the cyanuric acid level needs to be checked regularly to avoid chlorine lock.
TURNOVER:
Also called Turnover Rate, it's the period of time, in hours, required by the pump to circulate the volume of water in the pool.
A device that uses suction to collect dirt from the bottom and sides of a pool. Most common is a vacuum head with wheels that attaches to a pole and is connected to the suction line. Some automatic pool cleaners fall into this category.
