Review on Optimize CO2 Monitoring: JARDLI Glass Drop Checker for Planted Aquarium Tanks by Jacob Thorson

Very beautiful, elegant. But at first I had trouble keeping the suction cup in place. Turns out he would only stick Tribal on glass. If it's a plastic surface (one side of my aquarium is plastic for the internal filtration system and the opposite side is my CO2 diffuser) it keeps falling off. if it is softer, apply to a clean, dry glass surface and partially drain the tank. Tip for filling the pipette: use a 1 ml syringe. So I'm thinking of using a hanging drop tester over the aquarium instead (in an inverted U shape).