Q. I just started a 30-gallon planted aquarium, and for the first two weeks, the do-it-myself CO2 system was adequate. Unfortunately, I forgot my previous recipe, tried several other recipes, and no CO2 is being produced. I checked the system for leaks, and there are none. Here is my recipe for 1-liter soda bottles: 2 cups white sugar, 1 teaspoon baking soda, 1 teaspoon yeast and about 6 cups of water directly from the tap. I also added some corn syrup — but will this help?
San Jose, CA
A. I would use only 1 cup of sugar in a 1-liter bottle. Yeast converts sugar to alcohol, but it can stand alcohol concentrations of about 10 to 18 percent. Also, tap water usually has chlorine, chloramines and/or ammonia, which are harmful to yeast. If your tap water has chlorine added by the city water supplier, any conventional dechlorinator will do. If there are chloramines, you must not only break down the chloramines (which many water treatments do) but also neutralize the ammonia that results from this process. Only some conditioners do this. Look for those that specifically neutralize ammonia. Also, thoroughly wash and rinse the bottle to ensure no bacterial culture is fouling the fermentation. Good luck with your aquatic plants!