Basic Spa Care From 
by BioGuard
Glossary of Spa Terms
Get to know spa-related terms so you can talk with your SpaGuard® Dealer and better understand how your spa works.
Aeration
Process of mixing air and water. In a spa this can happen two ways: 1) Using an air blower to force air into an air channel or through the spa jets. 2) With Venturi Air Controls that allow air to be pulled into and mixed with the water in the spa jet.
Available Chlorine
Amount of hypochlorous acid (the active form of chlorine that does the work) a chlorinating product produces. Also referred to as Free Available Chlorine in the water.
Bacteria
Single-celled microscopic organisms. Pathogenic bacteria can cause infections, disease and bather irritation. Hypochlorous acid or hypobromous acid are used to kill bacteria in pool and spa water.
Balanced Water
Pool or spa water that has a proper pH and the appropriate mineral content to prevent corrosion and scaling.
Bromine
A member of the halogen family commonly used as a sanitizer or disinfectant to destroy bacteria and algae. It is resistant to heat and rapid pH fluctuations. back to top
Buffer
Chemicals that serve to prevent fluctuations in pH.
Chelant
Ingredient that prevents minerals and metals from scaling and staining.
Clarifier
A coagulant that gathers tiny particles together to make filtering them out much easier.
Corrosion
Etching, pitting and other destructive erosion of the spa surfaces and equipment due to low pH or chemical imbalance.
Filter Element
Device (cartridge) within a filter housing designed to remove suspended debris from the water.
Make-Up (Fill) Water
Fresh water used to fill the spa. Also called Source Water.
Oxidation
Chemical process for removing undesirable compounds from the water (see Shock Treatment). back to top
Ozone
Gaseous molecule composed of three atoms of oxygen (O3). In a spa, ozone is used to oxidize contaminants. Its instability and short life in the water require that it be used only to supplement chlorine or bromine residual to control bacteria.
pH
Measurement that indicates the acidic or basic nature of a solution. Measured on a scale from 0 to 14. Refer to chart on page 3 for acceptable ranges.
ppm
Parts per million. Unit of measurement used in measuring chemical application. Indicates the amount, by weight, of a chemical in relation to one million parts by weight of water.
psi
Pounds per square inch. Unit that measures filter pressure on a pressure gauge. Psi increases as the filter gets dirtier.
Pump
Motor-powered device that creates pressure and water flow by spinning an impeller to provide circulation through the filter and heater.
Saturation Index (SI)
Numeric value indicating whether water is scale-forming or corrosive. It factors in pH, total alkalinity, calcium hardness and water temperature. Ideal range is between -.3 and +.3. Not applicable to spas using Spa Sentry.
Scale
Mineral deposits - usually calcium carbonate - that form on spa surfaces and equipment due to excessive calcium in the water. Scale is more likely to form in heated water if proper water balance is not maintained.
Shock Treatment
Addition of an oxidizing compound for the destruction of nitrogenous and other undesirable compounds.
Skimmer
Device in the spa that continuously pulls in surface water and floating contaminants that are then removed by the filter. A hand skimmer net can be used manually to remove floating debris from the water.
Super-oxidation
Application of large quantities of oxidizing compounds to destroy chloramines, ammonia and other oxidizable compounds. It's done to get rid of odors and cloudy water, as well as for maintenance.
Total Alkalinity (TA)
The amount of alkaline components in water. TA acts as a buffer against rapid pH fluctuation.
Total Dissolved Solids ( TDS)
Measure of the amount of dissolved matter in the water. High TDS (2,500 ppm and higher) can interfere with the sanitizer's ability to combat bacteria growth. If TDS is above 2,500 ppm drain and refill your spa
