Acid
Chemicals such as muriatic acid or sodium bisulfate used to lower pH or alkalinity.
Acid Demand
A measure of the amount of acid required to reduce pH to a predetermined level. This can be accomplished by use of an acid titration procedure (Acid Demand Test)
Algae
Microscopic aquatic plant life which can grow on pool surfaces or float freely in the water though harmless to swimmers the presence of algae discolors the water and indicates improper sanitization. Black algae which grows on pool walls and floor can actually crack plaster finish.
Algaecide
A chemical used to kill existing algae or prevent the growth of algae.
Alkalinity
See Total Alkalinity.
Bacteria
Very small organisms continuously entering the water via swimmers, dust, etc. Without proper sanitization pools and spas are a perfect breeding ground for bacteria, many of which can cause disease or infection.
Balanced Water
Water that is neither corrosive nor scaling (in relation to pH, total alkalinity, calcium harness, and temperature factors). The Langelier Index for perfectly balanced water equals zero.
Base
A chemical which raises pH when added to the water, like sodium carbonate or caustic soda.
Base Demand
A measure of the amount of alkali material required to raise pH to a predetermined level. This can be accomplished by use of a base filtration procedure (Base Demand Test).
Bather Load
The number of individuals using a pool or spa in a 24 hour period and the pool and spas principal source of bacterial and organic contamination.
Break Point Chlorination
The process of shocking the water with significant quantities of chlorine to oxidize all contaminants and organic wastes and leave all remaining chlorine as free chlorine.
Bromine
Chemical sanitizer that kills bacteria and algae.
Buffer
Chemical that resists pH change, e.g. sodium bicarbonate
Calcium Hardness
A measure of the calcium salts dissolved in water.
Caustic Soda
Also known as sodium hydroxide and is used to raise pH.
Chloramines
A group of chlorine ammonia compounds formed when chlorine combines with organic wastes in the water. Chloramines are not effective as sanitizers and are responsible for eye and skin irritation as well as strong chlorine odors (also known as Combined Chlorine).
Chlorine
Chemical sanitizer that kills bacteria and algae.
Chlorine, Combined
The reaction product of chlorine with ammonia or other pollutants, also known as chloramines.
Chlorine Demand
Amount of chlorine required to react on various water impurities before a residual is obtained.
Chlorine, Free
Chlorine available to kill bacteria or algae. The amount of chlorine available for sanitization after the chlorine demand has been met. Also known as chlorine residual.
Conditioner
See Cyanuric Acid
Corrosion
The destruction of metal surfaces mostly due to low pH (below 7.0) and or low alkalinity.
Cyanuric Acid
Chemical used to prevent the decomposition of chlorine by ultraviolet (UV) light.
Disinfect
To kill and inhibit growth of harmful bacterial and viruses in pool and spa water.
Dry Acid
A granular chemical used to lower pH and or total alkalinity.
Langelier Index
A mathematically derived factor obtained from the values of calcium hardness, total alkalinity, and pH at a given temperature. A Langelier index of zero indicates perfect water balance (i.e.., neither corroding nor scaling).
Magnesium Hardness
A measure of the magnesium salts dissolved in water - not a factor in water balance.
Muriatic Acid
An acid used to reduce pH and alkalinity. Also used to remove stain and scale.
Non Chlorine Shock
An oxygen based shocking compound. Non Chlorine shock is fast dissolving so it allows swimming just 15 minutes after use.
Organic Wastes
Wastes such as saliva, urine, perspiration and sun tan oils which swimmers introduce into the pool or spa. Most organic wastes will not filter out and must be removed by shocking/oxidizing.
OTO
Test Regent used to test bromine and chlorine in pool and spa water.
Oxidizing
The process of breaking down organic wastes into simpler elemental forms or bi products. Also used to separate combined chlorine and convert it into free chlorine.
pH
A measure of the acidity of water. The pH scale runs fro 0 to 14 with 7 being the mid point or neutral.. A pH of less than 7 is on the acid side of the scale with 0 as the point of greatest acid activity. A pH of more than 7 is on the basic (alkaline) side of the scale with 14 as the point of greatest basic activity.
pH of Saturation
The ideal pH for perfect water balance in relation to a particular total alkalinity level and a particular calcium hardness level, at a particular temperature. The pH where the Langelier Index equals zero.
Phenol Red
Chemical reagent used for testing pH in the range of 6.8 - 8.4.
ppm
Abbreviation for parts per million.
Sanitizer
A chemical which disinfects (kills bacteria), kills algae and oxidizes organic matter.
Saturation Index
See Langelier’s Index
Scale
Crust of calcium carbonate, the result of unbalanced pool water. Hard insoluble minerals deposited (usually calcium bicarbonate) which forms on pool and spa surfaces and clog filters, heaters and pumps. Scale is caused by high calcium hardness and/or high pH. The regular use of stain prevention chemicals can prevent scale.
Shock
Also known as superchlorination or break point chlorination. Ridding a pool of organic waste through oxidization by the addition of significant quantities of a sanitizer or non sanitizing oxidizing agent.
Soda Ash
Chemical used to raise pH and not so much, the total alkalinity (sodium carbonate)
Sodium Bicarbonate
Commonly used to increase alkalinity of water, it also raises and stabilizes pH.
Sodium Bisulfate
Chemical used to lower pH and total alkalinity (dry acid).
Sodium Hydroxide
Also known as caustic soda, A by-product of chlorine generation/production and often used to raise pH.
Stabilizer
See Cyanuric Acid
Superchlorination
Application of large dosages of chlorine to destroy buildup of undesirable compounds in water.
Titration
A method of testing by adding a reagent of known strength to a water sample until a specific color change indicates the completion of the reaction.
Total Alkalinity
A measure of the acid-neutralizing capacity of water which indicates its buffering ability, i.e. measure of its resistance to a change in pH. Generally, the higher the total alkalinity, the greater the resistance to pH change.
Total Dissolved Solids (TDS)
The accumulated total of all solids that might be dissolved in water.
