CO2 Indicator_ISTA


CO2 Indicator_ISTA



CO2 Indicator

Why Do I Need a Drop Checker
Maintaining the appropriate CO2 level is critical in a planted aquarium. Too much CO2 may harm your fish, whereas too little CO2 decreases plant growth and allows algae to take over. The handmade CO2 Glass Drop Checker makes it easy for you to know the approximate CO2 level inside the aquarium by comparing the colour of the reagent.

When the drop checker is placed correctly in the aquarium, the colour of the indicator solution will turn lime green when the optimal concentration of 30 ppm of CO2 is achieved in the aquarium water. A yellow or blue colour compared against a pH indicator colour chart indicates too much or too little CO2 in the water, respectively.

• BLUE=Low CO2 levels -> Increase rate of CO2
• GREEN=Proper CO2 levels -> No action required
• YELLOW=High CO2 levels -> Decrease rate of CO2


  • Injecting 1CC of CO2 Indicator solution to the cap of CO2 Indicator. Adding aquarium water is not necessary.
  • Recommended period of solution change, once a month.   Solution change at every water change is not necessary.