section_path: Commercial uses/Minor uses
section_name: Minor uses
paragraph_text: Minor uses
  
  Carbon dioxide is the lasing medium in a carbon-dioxide laser, which is one of the earliest type of lasers.
  
  Carbon dioxide can be used as a means of controlling the pH of swimming pools, by continuously adding gas to the water, thus keeping the pH from rising. Among the advantages of this is the avoidance of handling (more hazardous) acids. Similarly, it is also used in the maintaining reef aquaria, where it is commonly used in calcium reactors to temporarily lower the pH of water being passed over calcium carbonate in order to allow the calcium carbonate to dissolve into the water more freely, where it is used by some corals to build their skeleton.
  
  Used as the primary coolant in the British advanced gas-cooled reactor for nuclear power generation.
  
  Carbon dioxide induction is commonly used for the euthanasia of laboratory research animals. Methods to administer CO include placing animals directly into a closed, prefilled chamber containing CO, or exposure to a gradually increasing concentration of CO. The American Veterinary Medical Association 's 2020 guidelines for carbon dioxide induction state that a displacement rate of 30–70% of the chamber or cage volume per minute is optimal for the humane euthanasia of small rodents. Percentages of CO vary for different species, based on identified optimal percentages to minimize distress.
  
  Carbon dioxide is also used in several related cleaning and surface-preparation techniques.