Why We Use Citric Acid to Clean Our Aquarium Equipment?

Citric Acid is a natural acid found in citric fruits. It provides us with a safe and effective means in the reef-keeping hobby to remove calcium carbonate, coralline algae, bacteria and other organic deposits from aquarium equipment.

  • It works!
  • It’s cheap and it’s safe in dry form
  • It’s environmentally friendly, doesn’t give off toxic fumes and it doesn’t smell (unlike vinegar).
  • It is a readily bio-degradable organic compound made up of carbon, oxygen and hydrogen molecules.

Citric Acid usually comes in two forms, monohydrate and anhydrous.  The practical difference between these two forms is that monohydrate is produced as a grain, much like sugar, and anhydrous is produced as a powder. Given that the citric acid is dissolved in water for the purpose of cleaning aquarium equipment it does not matter in which form it is obtained.

Citric acid powder has a long, multi-year shelf life provided that you keep the lid on thereby preventing moisture absorption. As a rough guide, use 1 cup to 4 litres of water mixed in a plastic bucket. The concentration is not critical, the more citric acid powder that you use, the longer it will last. When depleted, the solution will no longer dissolve the deposits, seen by the emergence of small bubbles on the surface of the deposit, and it can be safely discarded down the toilet.

However, do exercise some caution when using the mixed solution. Although not as aggressive as other common acids, it is nonetheless an acid. Therefore, always use gloves and safety specs when handling. Also, always add the powder to the water rather than the other way round to avoid super concentrated mixture from potentially splashing out of the container and remember to rinse your hands after use.