Measuring CO2 with a drop checker
Don’t know how to measure the CO2 in your planted tank? Try this CO2 tester or “drop checker”.
You just need to add drop checker indicator mix to the CO2 drop checker and wait. After a few hours, the liquid will turn a certain color. Blue means you have too little, yellow too much and green is just right. Easy, right?
PS: you can also order the mix and the drop checker as a set, which saves a few euros again.