Description: Glass Flower Design Aquarium Live Plant Moss Tank CO2 Diffuser  Specification: Material: Glass Inner diameter: 2.5cm External diameter: 4cm   Features: - Atomic pores on the ceramic disc breaks down Carbon dioxide into tiny streams of bubbles. - With high surface area per volume ratio. - Flower design     Instructions:   1.Turn drop checker up-side-down and place 3 drops of test solution into the drop checker.   2.Use a pipette (not include) to inject tank water into the drop checker.   3.You will see the color change on the solution according to Co2 content in the tank water.   4.Turn drop checker up-side-down again carefully、 and place the drop checker inside the tank below water level.    Package included: 1x CO2 Diffuser Aquarium