Join Date: Jan 2008
A bubble counter is not absolutely required. You can turn your CO2 slowly up until your fish start showing symptoms, and then dial it back down. Using this method takes some time, and can be stressful for more delicate species.
A drop checker takes some time to equilibrate to the CO2 levels within the water.
A bubble counter serves as an instant check to see how fast you are injecting CO2 into the aquarium.