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Water sanitation: Knowing the differences for proper care and maintenance

Water becomes corrosive when pH is too low, and scaling when the pH is too high—especially for areas with hard water.

By Claudio Azurmendi

The difference between owning a pool with a salt system and one that uses traditional means of sanitation may seem expansive. For many, the perception of salt pools is that they are maintenance-free and often times chlorine-free systems. Dispelling the myths about salt pools can be difficult, but as pool professionals there is a necessity to at least massage pool owner’s perceptions regarding salt pool maintenance and ownership. By dislodging the misconceptions about salt pools, service professionals will be able to lengthen the life of their customers’ pools and keep them sparkling throughout the summer.

What difference does it make?

The first step in tackling the differences and similarities between each pool type is to understand how salt pools actually work. No matter the salt pool cell or chlorinator manufacturer, all systems use an electrolytic chlorine generator (ECG). The inner hardware usually comprises titanium (Ti) plates that are coated with ruthenium (Ru) and/or other rare earth metals. These systems carry out the process of electrolysis whereby the chloride ion (from salt) is converted to chlorine gas (Cl2) by passing an electric current through saltwater.

When applied to water, chlorine gas immediately converts to hypochlorous acid (HOCl). The other byproducts of electrolysis of the chloride ion to hypochlorous acid are hydrogen gas (H2) and sodium hydroxide (NaOH). Hydrogen gas releases harmlessly into the atmosphere (the effects of the sodium hydroxide ion will be addressed later in the article). This brief summary of chlorine production via ECG in salt pools may not be news to readers; however, one of the most common misconceptions about saltwater pools is they are not chlorine pools. Politely educating salt pool owners on this point will go a long way towards properly maintaining their water. Once they realize adding more salt is not a cure-all, it will help steer these pool owner towards proper maintenance and treatment options such as supplemental shocking, scale inhibitors, and pH balancers.

An added boost may be necessary

Most ECGs handle routine chlorination along with weekly shocking with ease. Consumer salt chlorine generators running at 100 per cent output typically produce anywhere from 0.3 to 0.9 kg (0.7 to 2.0 lbs) of chlorine—assuming the ECG is operating at 100 per cent output, or on a ‘boost’ setting for 24 hours a day. During periods of heavy usage, rain or weather extremes, the chlorine output capacity of an ECG can be strained. Just like any other pool, an occasional oxidizer supplement outside of routine chlorination methods may be necessary.

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