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API pH Down Professional Size - 473ml

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API Ph Down Professional Size - 473ml pH UP is phosphate free and nitrate free therefore will not encourage algae growth.

pH DOWN lowers pH to make freshwater aquariums more acidic for fish and plants


  • Lowers aquarium pH

  • Follow API Easy Care Guide and use pH DOWN when:

    Addressing Water Problem Solving issues

  • pH is the measure of acidic or alkaline conditions of water.
  • A value of 7.0 corresponds to a neutral pH.
  • pH values about 7.0 are considered alkaline, and pH values below 7.0 are considered acidic.
  • Different fish need different pH levels to be healthy. Check the pH level using a pH Test Kit.
  • pH DOWN is designed to lower the pH of aquarium water where testing has shown pH to be at an undesirable level.
  • pH DOWN lowers pH and makes aquarium water more acidic.
  • pH DOWN is fast-acting, colourless, easy to use and will not cloud or colour the aquarium water.

  • pH DOWN is phosphate-free and nitrate-free therefore will not encourage algae growth.


  • Determine the pH of aquarium water with an API Test Kit.
  • To lower pH, add ½ tsp. (2.5ml) for each 95 litres of aquarium water.
  • For larger aquariums, add 1tsp. (5ml) for each 190 litres of aquarium water.
  • Take another pH reading before dosing again with pH DOWN.
  • Some fish may be more sensitive to pH adjustments greater than 0.2 in a 24 hour period, so changes of this magnitude should be done with extreme care.
  • Some water is high in mineral ions, such as carbonate and bicarbonate, which strongly buffers aquarium water and can resist a pH change or cause “pH rebound”. In these situations, repeated dosing may be necessary to lower pH.