Why Use Ozone?
Ozone and chlorine differ in how they oxidize other compounds. At pool or spa residual levels, chlorine becomes incorporated into the compound. This chemically alters the compound. In this fashion, chlorine combines with organic compounds in the water. These organic compounds include body oils, suntan lotions, cosmetics, dead algae and bacteria. These reactions consume a lot of chlorine – and chlorine is no longer available to function as a biocide and residual. The altered chlorinated organic compounds (combines) form scum lines and greases that clog filters, (remove) and form layers with calcium carbonated which result in the formation of soft-scale.
At operating residual levels, chlorine also combines with nitrogen-containing compounds to form chloramines. Chloramines are less effective biocides than the killing forms of chlorine. Chloramines are responsible for the eye and skin irritations associated with chlorinated water. The formation of chloramines consumes considerable amounts of the free available chlorine. More chlorine needs to be added to establish a sufficient free chlorine residual in the water, a process known as “superchlorination” or “shocking”.
Ozone acts as a primary oxidizer, not as a disinfectant or biocide. Disinfection is achieved by maintaining a free available chlorine or bromine residual. Because Ozone is a more powerful oxidizing reagent than chlorine, Ozone reacts with organic or nitrogen containing compounds faster. Ozone does not combine with other compounds; instead, it causes the organic and nitrogen compounds to break apart. The smaller molecules are more water soluble, and some can even gas-off. Amine compounds are altered so that they no longer combine with chlorine. Ozone stops the buildup of chlorinated organic and amine compounds and does not form combines.
To summarize, chlorine’s biocidal and residual properties are excellent, and in pool and spa water, chlorine is the primary biocide and the free available residual. Ozone is the primary oxidizer. Ozone increases chlorine’s effectiveness as a biocide and residual.
Without Ozone, the homeowner uses much more chlorine to keep a free available residual and requires “superchlorination” or “shocking” compounds and other specialty chemicals to treat problems caused by pool oxidation by chlorine.