Provides reliable accurate, worry free CO2. It is 100% natural and economical. You don't need any expensive equipment. Perfect for smaller gardens and areas with limited ventilation, Excellofizz releases optimal amounts of carbon into the growth environment. Carbon is the building block for all plants, and proper absorption greatly increases plant mass and fruit load. HOW TO USE Place 3 FL OZ (100 ml) of water in a container. You will need one (1) puck for each 10 cubic feet of area. Place puck in water. Leave lid open slightly. Puck will dissolve slowly.