Replacing hazardous chemicals with carbon dioxide (CO₂) for pH stabilisation in swimming pools delivers a range of benefits including an improved safety profile for staff and bathers, increased bather comfort, and a milder impact on the pool structure and the environment. In water, CO₂ forms a mild carbonic acid that also helps maintain alkalinity and reduce total dissolved solids. It forms a natural bicarbonate buffer which minimises peaks and troughs of pH.
The most widely used method is chlorination with sodium hypochlorite. However, it has its limitations. If the pH of the pool water is not kept between 7.2 and 7.6 the chlorinated water could cause eyes, skin and mucous membrane irritation to the pool users. At the same time, it would also become corrosive to pool's equipment.
Historically, pH control has been carried out with harsh solvents (mineral acids) that can be dangerous to handle. Carbon dioxide offers a clean and safe alternative for pH correction. When dissolved in water, CO₂ reacts to form carbonic acid, a weak acid capable of safely reducing the pH to the desired value. Recuperated from natural processes, it is also an environmentally friendly solution.