Co2 indicator

A CO2 indicator for a planted tank is a device that helps monitor the level of carbon dioxide in the aquarium water, which is important for the growth and health of aquatic plants. It typically consists of a small plastic container filled with a special liquid that changes color in response to the level of CO2 in the water. By observing the color of the liquid, aquarists can adjust their CO2 injection system or other methods to maintain the ideal level of CO2 for their plants.