With the consumer becoming more aware of the disinfection byproducts produced from chlorination, the consumer is actively seeking a chlorine free technology to maintain a pool or spa.  There is a world of confusion related to these chlorine alternative technologies.   How can one possibly sanitize a swimming pool without chlorine?  These chlorine free / chlorine alternative technologies have been around for many years.  Since most of these technologies are available directly from the manufacturer, the middle man is cut out and this means a cost savings to the end user.

There needs to be a distinction between “chlorine free” and a product that claims to “reduce the need for chlorine”.   Many chlorine free or reduced chlorine technologies used to maintain swimming pools are listed below:

Mineralizes, such as the Nature2®, utilizes a cartridge containing a combination of copper, silver, and other trace elements to reduce the need for chlorine.  A system of this type cannot eliminate the need for chlorine but it does effectively help control algae and bacteria growth with less chlorine demand.  The reason is that neither copper nor silver is being released into the water in an ionic form and no sanitation residual can be established.  Therefore it is not a chlorine free alternative.

Ozone systems uses for pools are very popular.  There are two basic types.  One being an Ultraviolet (UV) Ozone Generator that uses 184 nm spectrum light to create ozone (This is not the same equivalent as the 254 nm used for UV sanitation).  The second type the Corona Discharge Ozone Generator that utilizes an electrical field to produce ozone.   Ozone is a strong oxidizer that is naturally occurring.  It can oxidize contaminants that are too small for your filter to capture.  Pools are open bodies of water and the units used for pools and spas are way too small to replace the need for chlorine altogether.   The gas has a very short life and dissipates before it can be circulated throughout the pool.  Ozone can, however, reduce contaminants that combine with chlorine lowering the levels of chlorine required.  Therefore, it also is not chlorine free.

Ultraviolet light is an impressive sanitizer in closed loop systems.  At 254 nm wavelength, it can kill or deactivate just about any water borne pathogen.  The problem with this being marketed to the swimming pool industry is that the only sanitation that takes place in a foot long quartz sleeve.  Meaning, there is not residual to kill what is in your swimming pool, only what travels though your plumbing and pool filter.  If algae can double itself every 15 minutes and most bacteria at an exponential rate, a UV system cannot sanitize fast enough.  Chlorine reduction is very small when using these systems and is the least economical for a swimming pool.  Just like the mineralizer, and ozone, a sanitation residual can not be built up to kill microbes and it would not be considered a chlorine free alterative.

Baquacil® is primarily polyhexamethylene biguanide and SoftSwim® is mainly comprised of Poly(iminocarbonimidoyliminocarbonimidoylimino-1,6-hexanediyl), hydrochloride.  Both have been marketed as a chlorine alternative and are distributed though pools stores mainly.  Both have a proprietary chemistry and but are often referred to being a peroxide based chemistry.  These products are effective but they are absolutely the most expensive alternative to chlorine.

Ionizers have been around for 40 years.  Ionization utilizes an electrical current to convert an atom into an ion.  These ions are pulled from a cathode and are carried downstream into the pool or spa.  As the water recirculates through the electrode, an ever increasing residual of ions are developed.  Metals and/or alloys that are commonly used are copper, copper/silver, copper/zinc (brass), and copper/silver/and zinc.  It is important that ionizers can produce enough current to supply sufficient ions into the water.  Some smaller units that cannot achieve over 0.3 ppm of a residual would require chlorine as well to sanitize.  However, units that can be sized to a body of water and achieve residual levels over 0.5 ppm can replace chlorine totally as a sanitizer.  Ionization is the most cost effective chlorine free technology available on the market today.  A clarifier or a non-chlorine oxidant may need to be utilized to assist in the clarity of water with ionizers.