Aqua One CO2 Permanent TesterKeep track of the Co2 levels in your aquarium with this handy CO2 permanent tester.The liquid in the vial changes colour depending upon the C02 levels.Carbon dioxide (CO2) assists your aquatic plants to grow and thrive. Without sufficient combinations of CO2 and lighting, aquatic plants are unable to photosynthesise and grow.Suitable For: Coldwater and Tropical Planted Aquariums
