co2 in the water , and selzer water are best with ice and burbon, or rum. You see the plant takes co2 in in the day time and expells it at night. The roots will not uptake co2 unless your fan is in the resivore. Now it will cause the ph to get upset, thats why no one uses it. Now you add co2 between 1500 ppm when the lights are on, and vent when the lights go off . Plus you need to raise the exust temp to 95 deg f. so the plants will use the extra co2. The yeast and sugar works best if you make beer or wine at the same time. Using the bubble counter to find out how much you have put in the grow space. Your best thing is to use lots of fresh air as it has 300 ppm on earth.