Co2 Drop Checker

An Aquarium Glass CO2 Drop Checker Set is an essential monitoring tool for planted aquariums, providing a real-time visual assessment of dissolved carbon dioxide levels. Crafted from hand-blown laboratory-grade glass, the drop checker utilizes an internal air-gap chamber to trap outgassed CO2 from the water column, reacting with a pre-mixed 4dKH bromothymol blue indicator solution without mixing with the aquarium water. The solution shifts color dynamically to indicate CO2 concentration: blue signals under-saturation (insufficient CO2 for plant growth), green indicates optimal saturation (~30 ppm CO2 for vibrant flora and fish safety), and yellow warns of dangerous over-saturation. Compact and elegant, it mounts discreetly inside the tank using a suction cup to deliver clear, continuous, and reliable water chemistry feedback.