i saw a difference not a huge difference. The new growth from the plant was healthier, fuller and thicker. So even if its not as much Co2 as a using large tanks but a hell of a lot cheaper and its the same thing.
i use a liter bottle for themirco grow it takes about a 1-2 weeks before i need to make another. i heard that if you add a tiny bit of baking soda it doesn't foam so i have been doing that. it seems to increase the amount of bubbles that are produced and i think helps it stay longer.
only disadvantage is that it stinks after a while. first like pizza dough then like pure alcohol. Its 14% alcohol by valume. standard amount you can get from yeast alone, before distilling it.