ACID:  Liquid (muriatic acid) or dry granular (sodium bisulfate) substance used to lower the pool's pH (toward a more acidic condition) or to lower total alkalinity levels.

ACID DEMAND:  A titration test used to determine proper amounts of acid (or pH decreaser) to reach correct levels.  For example, to lower pH from 8.0 to 7.6, your pool may "demand" 2qts. of acid.

AIR BLEEDER ASSEMBLY:  Located on the top of the filter and sometimes accompanied by a pressure gauge, the bleeder is opened to release air trapped in the filter.

ALGAE:  Over 20,000 species known to exist.  Algae may form on your pool surfaces or it may bloom in suspension.  We typically know algae to be 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.  Pink algae is not algae at all but a form of bacteria.  Algae are living breathing organisms that need warmth, sunlight, and COČ to thrive.  Click here to learn more about algae and how it affects your pool.

ALGAECIDE:  Meaning, to kill algae. Algaecides perform best as a backup to a routine sanitation program. They also help to kill airborne spores as they blow into the pool. A variety of algae treatment products are available including copper and silver compounds, poly-quat compounds, chlorine enhancers , and herbicides.

ALGAESTAT:  An algaecide kills algae, while an algaestat retards and prevents its genesis and growth.

ALKALINE: Alkalis are best known for being bases (compounds with pH greater than 7) that dissolve in water. Alkaline is commonly used as a synonym for base, especially for soluble bases.

ALKALINITY:  Alkaline refers to the condition where the water's pH is above 7.0 (neutral) on the pH scale.  It is the opposite of acidic.  Alkalinity is the amount of carbonates and bicarbonates in the water,  measured in "parts per million" (ppm) of Total Alkalinity.

ALUMINUM: A silvery white and ductile member of the poor metal group of chemical elements

ALUMINUM SULFATE:  Also known as "alum;" this product is used as a flocculent which attracts suspended particles in the water together (green or cloudy pools).  "Alum" sinks everything to the bottom  which is then vacuumed to waste.  A small amount of "alum" can also be used as a sand filter additive. 

ANION: A negatively charged ion, which has more electrons in its electron shells than it has protons in its nuclei, is known as an anion due to its attraction to anodes.

AUTOMATIC POOL CLEANER:  A device which agitates or vacuums debris from the walls and floor of the pool.

BACKFILL:  The repositioning of the soil after construction of a pool.

BACKWASH:  The process of thoroughly cleaning the filter medium and/or elements by reversing the flow of water through the filter to waste.

BACTERIA:  From a health perspective, the most dangerous micro-organisms which may be living in the pool water.  Some are pathogens, which can cause infectious diseases.

BACTERICIDE:  Kills bacteria.  Chlorine is a bactericide and germicide.  Silver algaecides are actually more bactericide, and are useful on pink "algae."

BASE:  Those chemicals of alkaline nature which will counteract the pH of an acid eventually neutralizing at 7.0. Common bases used around the pool would include Soda Ash, Sodium Bicarbonate, Sodium Carbonate, and Sodium Sesquicarbonate.

BASE DEMAND:  A titration test used to determine proper amounts of base (pH increaser) to reach correct levels.  For example, to raise pH from 7.2 - 7.6, your water may need 2 cups of soda ash.

BIGUANIDES:  The name for a certain class of sanitizers using the polymer PHMB, the only non-halogen sanitizer available for pool and spa use.  "Soft Swim" and "Baquacil" are manufacturers of this technology.
 

BICARBONATE: An intermediate form in the deprotonation of carbonic acid.