How CO2 Can Affect Your Pool’s pH Levels

a swimming poolSo you may have heard about using carbon dioxide, or CO2, in pools as a replacement of muriatic acid to help maintain and regulate pH levels. It has become increasingly popular as the storage and application of CO2 has become easier and more user-friendly. There are even some people who use frozen CO2, or dry ice, to control the pH in their pools. These pool owners basically just throw in the right amount of dry ice for their pool, and then it helps regulate the pH in the pool. Though it’s good to wait until the dry ice dissipates, it is a much easier way to balance the pH levels in your pool, than acids and other chemical compounds.

CO2 Advantages for Your Pool

CO2 carries a number of advantages over mineral acids, hydrochloric acid, and sodium bisulphate.

  • CO2 is an odorless, colorless, non-flammable gas. It’s very easy to administer and handle, and it’s only danger lies in its being released in a confined area, where it will cause anyone near it to choke and asphyxiate. No special equipment is required for handling.
  • Typically a pool’s owner/operator must determine risk assessment when selecting which chemicals will be used in the pool. The initial step should be to ascertain whether or not a chemical process can be eliminated. CO2 allows this to happen
  • Spilling of CO2 is very rare, so emergencies involving carrying and delivery of CO2 are extremely rare. No special safety monitoring is required for leakage, unless in a confined space.
  • Different from mineral acids, it’s impossible to mix carbon dioxide with sodium or calcium hypochlorite in liquid form through spillage or operator error. Essentially this means that there isn’t a co2 tankspossibility of accidentally creating chlorine gas, and that is a huge advantage over standard pool chemicals.
  • CO2 also allows for improved process control, due to its natural buffering quality. It basically gives you more accurate control when reducing pH levels, which is much easier than trying to accomplish it with mineral acids and chemical compounds, albeit at a slower rate. The fact that CO2 has a pH of 5, while HCL acid is 30% really give a better scenario because swimming pool water doesn’t typically take a sudden dose of chemicals very well.
  • Lastly, there is zero secondary pollution from CO2 like you’d normally get from hydrochloric acid or sulphates. The introduction of CO2 into pool water will enhance the chemical equilibrium by forming carbonates and bicarbonates. This will contribute to complete dissolved solids levels, but will not contribute to alkalinity that corrodes.

Additional benefits of CO2

Studies have shown that using CO2 will slightly reduce the carbon footprint of each swimming pool, and produce fewer greenhouse gasses. Other studies have shown that pools that switched from hydrochloric acid to carbon dioxide consumed less chlorine, smaller percentages of oxidants floating just above the pool, and an overall lower alkalinity in swimming pools.

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