For the continuous, exact control of CO2 content in the aquarium.

CO2 long-term test Correct + pH

Keeping tabs on CO2 content at all times

The colouring of the special CO2 indicator varies according to the CO2 content from

  • blue = not enough CO2 to
  • green = CO2 content ideal and
  • yellow = too much CO2.

The level of CO2 in the aquarium can be read directly from the six-colour scale in milligrams per litre. This provides an absolutely simple and reliable means of setting the correct CO2 supply level.

Special CO2 indicator for particularly simple and accurate CO2 control

Conventional long-term CO2 tests are filled with a mixture of aquarium water and indicator. This involves various disadvantages, one being that the acids which are present in all aquarium waters (e.g. humic acids, nitrate, etc.) can lead to incorrect test results. The DENNERLE CO2 long-term test Correct employs a ready-to-use special CO2 indicator which is used on its own, rather than in a mixture with aquarium water.


The key advantages:



No additional measurement of carbonate hardness is necessary. Only a single colour-matching scale is required.


The CO2 long-term test Correct +pH indicates the CO2 content correctly at all times – independently of other acids in the aquarium water (e.g. humic acids). Measuring accuracy now also remains unaffected by any changes in carbonate hardness as a result of increases in the hardness of the water, evaporation or water changing


The CO2 long-term test Correct allows direct determination of the CO2 content in millilgrams per litre – avoiding the need for additional water measurements and the laborious practice of converting values in tables.  The test is equally efficient at low carbonate hardness levels.



In addition to the CO2 concentration, the pH value can also be displayed on a 6-colour scale. Here this depends on the carbonate hardness. For each carbonate hardness measured, there is a corresponding 6-colour scale provided in the package. Here the pH value can now be read easily using the colour of the CO2 special indicator.


Complete set, comprising:

  • Test container
  • Special CO2 indicator
  • Six-colour matching scale
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