Amateur Athletic Union – A National organization with a division devoted to the athletic aspects of swimming.
ABRASION HAZARD
A sharp or rough surface that would scrape the skin upon chance or by normal use modes.
ABSOLUTE FILTER RATING
Filter rating meaning that 99.9 percent of essentially all of the particles larger than a specified micron rating will be trapped on or within the filter.
ABSORPTION
The process of substance actually penetrating into the structure of another substance. This is different from adsorption in which one substance adheres to the surface of another.
ACCELERATION
The rate at which velocity changes.
ACCESSIBLE
Easily exposed for inspection and the replacement of materials and/or parts with the use of tools.
ACIDIC
The condition of water or soil, which contains a sufficient amount of acid substances to lower the pH below 7.0.
ACTIVATED CARBON
A form of elemental carbon whose particles have large surface area with adsorptive qualities, primarily used to remove chlorine, objectionable tastes and odors and numerous toxic organic compounds from water. Produced by heating carbonaceous substances, bituminous coal or cellulose-based substances such as wood or coconut shell, to 700 degrees Centigrade or less in the absence of air to form a carbonized char and then activating or oxidizing at 800 to 1000 degrees Centigrade with oxidizing gases such as carbon dioxide or steam to form pores, thus creating a highly porous adsorbent material.
ACTIVATED CARBON BLOCK
A blend of fine activated carbon, water and a suitable binders(such as polyethylene or similar material) that is mixed and molded and hardened or extruded to a cartridge filter of any size and shape. Occasionally specialized media are added along with activated carbon to provide customized performances of specific contaminants such as lead.
ADSORPTION
Attachment of a substance to a solid (or liquid) surface by non-specific means(as with carbon filtration techniques)
AERATION
The process of adding air to a water supply for the purpose of oxidation(of materials such as iron, manganese, etc.)
AIR INDUCTION SYSTEM
A system whereby a volume of air (only) is induced into hollow ducting built into a spa floor, bench or other location. The air induction system is activated by a separate air power unit (blower).
AIR PUMP ASSIST BACKWASH
The compressing of a volume of air in the filter effluent chamber (by means of an air compressor or by the water pressure from the recirculating pump) which, when released, rapidly decompresses and forces water in the filter chamber through the elements in reverse, dislodging the filter aid and accumulated dirt, carrying it to waste.
AIR VOLUME CONTROL
A device that maintains the air charge in a standard water storage tank. Pre-charged tanks do not require an air volume control.
ALGAE
Green, black or brown microscopic plant life which is nourished by sunlight. A group of single-celled plants, which includes both seawater and fresh water varieties.
ALGICIDE
A chemical or process for killing algae. An algistat is an agent for preventing their growth.
ALKALINITY
A measurement of the quantity of chemicals present in water, which can neutralize acids. These include carbon dioxide, bicarbonate, carbonate and hydroxides. pH conditions which exceed 7.0.
ALUM
A flocculating agent. Potassium and ammonium alum are the most common types used in the treatment of pool water. Aluminum sulphate is often used with gravity sand filters.
ALUMINUM SULFATE
An aluminum salt commonly used as a flocculent by municipal water treatment facilities.
AMPHOTERIC
A substance, such as aluminum, capable of acting as either an acid or base.
AMPS
An electrical measurement of motor performance where current(amps) = voltage(volts)/resistance(ohms). Amps measures the flow of electricity.
ANAEROBIC
A condition in which there is no air or no available free oxygen. Sometimes relates to microbes, which can exist without oxygen.
ANIONS
See ion.
ANSI
American National Standards Institute
AQUIFER
Any geological formation containing water; one that supplies water for wells, springs, etc.
AREA
The space on a flat plane bordered by two lines that can be measured in two directions (Length x Width = Area).
ASME
American Society of Mechanical Engineers
ATMOSPHERIC PRESSURE
The weight of the atmosphere at a given point on earth.