At first, learning to understand spa water chemistry can seem like a daunting task to say the least. We intend on helping you understand spa chemicals so that you can maintain the health of your spa at the best level possible.
There are three basic principals to spa water chemistry.
- Sanitize/Disinfect (kill viruses, germs, etc.)
- Oxidize (break down organic compounds like oils and sweat)
- Maintain slightly base (alkaline) water (pH of 7.4 – 7.6). This controls the corrosiveness of the water, prevents excessive scaling (mineral formation on surfaces exposed to water, and insures that the water is comfortable to the skin.
Once you have a good understanding of the chemicals that are used in your spa, you will be able to maintain proper water balance. Water balance is reached when all elements (pH, total alkalinity, calcium hardness and total dissolved solids) are within their proper ranges.
 | IMPORTANT! Always read directions on chemical container thoroughly before using spa chemicals. |
 | The pH scale goes from 0 to 14, with zero being extremely acidic and 14 being extremely base (alkaline). Seven is considered neutral pH. |
The following definitions for chemicals will help you understand what
the chemical is and what it is used for:
Sanitizers
CHLORINE – Chlorine is widely used as a sanitizer in pool and spa water to kill bacteria, viruses and algae, it also oxidizes ammonia and nitrogen compounds such as swimmer waste. Its formal name is Sodium Dichlor and is referred to as a chlorinated concentrate. Sodium Dichlor is a fast-dissolving, granular, stabilized organic chlorine compound providing either 56% or 63% available chlorine. Cyanuric acid and/or stabilizers are added to prevent U.V. light destruction of the chlorine by the sun. Use of improper Chlorine additives can cause excessive Cyanuric acid which can corrode and destroy spa components.
BROMINE – Bromine is the other commonly used sanitizer or disinfectant in pool and spa water to kill bacteria and algae, and oxidizes ammonia and nitrogen compounds such as swimmer waste. This chemical does not eliminate swimmer waste unless it is combined with an appropriate oxidizer such as a non-chlorine shock. It is susceptible to direct sunlight, and is therefore not efficient in outdoor pools. Bromine is sometimes used as an alternative for people whom are allergic or sensitive to chlorine products. Bromine products are available as sodium bromide and bromine tablets. The bromide ion has no effective disinfectant or sanitizing capabilities without the use of non-chlorine shock (potassium monopersulfate). Potassium monopersulfate is added to oxidize, or activate, the bromide ion into bromine, which rapidly forms the active sanitizer hypobromous acid in the spa water. Upon reaction with bacteria and other spa contaminants, hypobromous acid is reduced back to bromide ion, ready to be activated again by the next dose of potassium monopersulfate. Potassium monopersulfate begins to produce bromine immediately and continues to do so for several hours, providing time for oxidation of bather waste and other organic contaminants such as ammonia and nitrogen.
NON-CHLORINE SHOCK (Potassium Monopersulfate) – Also known as “Oxy- Shock”, is an important chemical used in the process of disinfecting and sanitizing the spa water. Non-chlorine shock is used to oxidize and eliminate organic contaminants, dead algae and debris, and will also convert the chlorine by-products (chlorides and chloramines) back into free available chlorine.
When used with bromine products, non-chlorine shock is used with sodium bromide in a two-part disinfection system. Potassium monopersulfate (non-chlorine shock) is added to oxidize, or activate, bromide ion into bromine which rapidly forms the active sanitizer – hypobromous acid – in spa water. Upon reaction with bacteria and other spa contaminants, hypobromous acid is reduced back to bromide ion, ready to be activated again by the next dose of potassium monopersulfate. Most non-chlorine shock products have buffers that reduce pH instability, and corrosion inhibitors that help protect the heater and other metal surfaces.
OZONE – Ozone is a powerful gas that is used as a sanitizer and an oxidant to keep spa water clean and disinfected. Although ozone is about 3000 times more powerful than chlorine, it has a tendency to dissipate quickly and does not create any sanitizer residual. By using an ozonator for your spa, you can cut maintenance time and chemical costs by as much as 75%. Ozone is manufactured by an ozonator (ozone generator) and is dispensed during the filtration mode.
pH Controllers
SODIUM BICARBONATE – Commonly used to increase pH and total alkalinity of spa water. Sodium bicarbonate is also known as natural baking soda. SODIUM CARBONATE – Also known as soda ash, is a substance used to raise pH and total alkalinity
SODIUM BISULFATE – Also known as dry acid, the chemical used to lower pH and total alkalinity of spa water.
Water Conditioners
FLOCCULENT – A compound which clarifies spa water by gathering oils, dirt, scum, metal deposits and small contaminant particles into larger globules, which then can be filtered more effectively.
CLARIFIER – A compound used to remove dissolved solids, metals, dirt, oils, or other contaminants from spa water.
SCUM BALL™ – A softball sized ball that is kept in the water. The ball is chemically treated so that it attracts contaminants that would normally be trapped in the filter.
SEQUESTERING AGENT – Stain and scale preventing compounds that sequesters dissolved metals to prevent water discoloration.
CALCIUM CHLORIDE – A soluble white compound used to raise the calcium hardness of spa & pool water, to protect equipment from corrosion.
ALGAECIDE – A chemical used to kill algae and prevent it from growing back.
DEFOAMER – A compound used to reduce or eliminate foaming in spa water.
CHITIN – A naturally occurring polymer (pronounced KY-tin) found in crab and lobster shells. As a spa clarifier, it is the best flocculating agent available. Removes oils, dirt, scum, and metal deposits, allowing the filtering system to work more effectively