This product requires CO2 Drop Checker Solution to work. You can purchase CO2Art’s Drop Checker Solution HERE.

CO2 is one of the most important nutrients for aquarium plants. At the same time, too much CO₂ can hurt other organisms of the aquarium. For this reason, long term monitoring of the CO₂ levels in the aquarium is highly recommended.

1. Pour CO2 solution into the Drop Checker
2. Place Drop Checker in to the aquarium
3. The color will change according to the concentration of dissolved CO₂ in the aquarium water after roughly 2 hours.
4. Green will indicate a proper CO₂ value | yellow will indicate to much CO₂ | and blue will show not enough CO2.

Please note that the required CO₂ Drop Checker solution is sold separately and does not come with this glass CO₂ Drop Checker.