I just made my best batch of co2. 1 gallon milk jug, push a sharp pencil through the middle of cap, insert airline and hot glue to seal. 2 cups white sugar 1 cup melted brown sugar 1 cup cranberry juice 1 spoon baking soda After adding all ingredients and shaking vigorously I added 1 pack of dry yeast and filled jug 3/4 with hot water from facet. Easy recipe but I tried the juice for fun and it might be the secret P.S I wouldn't try this recipe unless you have a well oxygenated aquarium. The co2 out put is pretty crazy half my bubble wand is going nuts.