about your co2 carbonated water, it does work, but try to keep that to a minimum as the water droplets act as magnifying glasses to you plant and could burn them. other cheap supplements for co2 are you breath (breath on them when you are visiting them), vinegar and baking soda is good. sugar,water, and yeast (but NOT for hydroponics, that could screw your whole system with a yeast infection!!!) and ONLY if you are around, you can use a candle as it lets off co2 as it burns oxygen. make sure you put it in an empty coffee can and ALWAY be around and put it where nothing is abovie the coffee can. some cheap ways to get some co2.