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Green Aqua Glass CO2 Drop Checker

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Green Aqua Glass CO2 Drop Checker (Nano)

Drop checkers are used to monitor the CO2 levels in the aquarium: the pH indicator solution inside the bulb section will change color according to the amount of CO2 dissolved in the aquarium water. Blue and dark-green colors will indicate low CO2 levels, light-green (lime-green) is OK, yellow is too much. Note that drop checkers always have a delay of 2-3 hours, so they show a CO2 level that was present hours before the reading (delayed reading).

The drop checker is the best tool to monitor CO2 levels continuously. With some practice and experience it can be a precise tool to measure the amount of CO2 dissolved.


  • Turn the drop checker almost all way upside down holding the suction-cup.
  • Start dripping the blue CO2 reagent into the drop checker.
  • While dripping, modify the angle of the upside-down-held drop checker, allowing it to fill up with liquid.
  • You should stop when the modified angle is so horizontal that the reagent is no longer flowing down into the spherical part (bulb section).
  • Turn the Drop Checker back to normal position (with the opening at the bottom)
  • Clean the inside of the opening free of any drips of reagent with a kitchen towel.
  • Put the drop checker into the aquarium using the suction-cup.

Do not forget, that CO2 is not dissolved uniformly into the aquarium water. On a computer model it would look more like "clouds in the sky"... Levels are higher at the injection point and they will be lower at far sides of the fish-tank, with slow water movement. So Drop Checker values will only show the amount of CO2 dissolved at the location of the measurement. Make sure to move the Drop Checker to other parts of your aquarium in order to discover the different levels. Always leave the DC at the same place for at least a day to allow it to calibrate properly. Do not forget, that it shows the levels with 2-3 hours delay.

Do not make any sudden changes in the CO2 bubble count. That can result in algae bloom or fish health problems (yellow drop checkers will often signal fish health problems). 95% of all algae-issues are CO2 related! Make small changes and observe the Drop Checker color change in 2 hours.

IMPORTANT: You will also need a Drop Checker Reagent (sold separately) to use this item.

More Information
NameGreen Aqua Glass CO2 Drop Checker
Weight (kg)0.100000
Is on SaleNo
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Green Aqua CO2 indicator reagent 10 ml Previous Green Aqua CO2 indicator reagent 10 ml
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