Plants require CO2 to grow and remain in optimal condition. In a standard planted aquarium, there is a limited supply of CO2. Simple and safe, the CO2 Natural Plant System is by far the most reliable and natural method to supplement CO2.For aquariums up to 20 GallonsThis system is designed to supply any aquarium with a safe, economical, and efficient method of providing nature’s most powerful carbon source for plants. Employing a natural fermentation process for CO2 eliminates the need for inconvenient pressurized cylinders. It allows quick, easy, and affordable refills of ingredients to provide continuous CO2 for a 3-4 week period. Our special fermentation canister was developed to support consistent carbon dioxide output.