Sanitizers

Sanitizers are the chemicals or device that kills or inactivates micro-organisms in the swimming pool or spa water. They also carry out additional functions: oxidizing organic contaminants (ie. Body oils, cosmetics, perspiration, garden material, etc.) and eliminating algae.

Studies have shown that oxidation accounts for approximately ninety per cent of sanitizer consumption while sanitation accounts for ten percent.

All swimming pools and spa’s must contain a sanitizer residual. The best way to ensure the residual is to use some type of product that constantly adds sanitizer to the water (i.e. chlorine pucks, bromine pucks, chlorine feeder, etc). If chlorine or bromine pucks are used it is advised to house them in some type of canister to prevent rapid erosion, and thus excessive residual levels. The pool or spa should be shocked once a week to eliminate chloramine, oxidize organic material and kill algae spores (see shocking).

Following is a brief overview of the main swimming pool / spa sanitizers

CHLORINE

In its purest form (Cl2 gas) chlorine is both toxic and unstable. Normally chlorine is combined with other elements to produce less dangerous products that can be easily handled and stored. These products, called sanitizers, are used in swimming pool water to kill germs, bacteria and algae. They also remove microscopic particles from the water which would normally pass through the filter.

Chlorine present in swimming pool water may be divided into two groups, FREE CL and TOTAL CL. Free chlorine is the active sanitizer and/or oxidizer. When chlorine comes into contact with algae, bacteria or germs it produces a toxic byproduct called Chloramines. (Please note : Chloramines are responsible for the excessive chlorine smell and stinging eyes commonly found in public pools). To eliminate the chloramines the pool should be shocked (see Shocking). Total Chlorine is the sum of free chlorine and chloramines in the water.

Granular Chlorine

• Calcium Hypochlorite or granular chlorine
• Economical, powerful oxidizer used for shocking swimming pool water. Not recommended for maintaining a chlorine residual, due to its instability
• Not completely soluble
• Raises pH of water

Stabilized Chlorine

• Tri Chloro or inorganic chlorine
• Very powerful, soluble oxidizer
• Automatically replaces stabilizer in water lost through backwash or spillage
• Does not change the pH of the water
• Not applicable to indoor pools
• Expensive

Liquid Chlorine

• Least powerful chlorine product
• Prevents localized staining when added to pool
• Bulky and difficult to use
• Highly unstable, dictating storage position and time
• Raises pH of pool water

Stabilized Pucks

• Compressed stabilized chlorine
• Gradual release of sanitizer, providing a good chlorine residual
• Stable product, preventing degradation due to sunlight or extended storage
• Fully soluble
• Does not affect pH of the pool
• Convenient, safe and easy to use
• Not applicable to some indoor applications

Bromine

Bromine is an effective sanitizer used predominantly in spas and indoor swimming pools. It is available in many forms and may be added to the swimming pool or spa in the same manner as chlorine. The main byproduct of Bromine sanitation is Bromamines. Unlike chlorine, these bromamines produce no smell and still retain some of their oxidizing and sanitizing power. They may be re activated (back to active Bromine) by “shocking” (see Shocking) the water with any type of oxidizer (Chlorine, Bromine or a non chlorine based shock).

Bromine is not recommended for outdoor installations. Given its instability, low oxidizing potential and reliance upon algaecides it proves to be an expensive alternative to chlorine.

Once bromine has been introduced to a swimming pool the pool can not be stabilized or converted back to chlorine. Any time an oxidizer is added to the swimming pool it is consumed rejuvenating the bromine. If you want to revert back to chlorine, you must completely drain the pool.

Bromine VS Chlorine

• Bromine performs far more efficiently at higher temperatures, therefore making it compatible for hot tub use
• Bromine produces very little smell once dissolved in water
• Chlorine provides far more protection against algae and bacteria
• Chlorine has greater oxidizing potential
• Bromine is expensive
• Bromine is unstable in sunlight and cannot be stabilized. It is therefore incompatible for outdoor swimming pools and spas.