Many thanks to all of you who wrote on- and off-list in reply to my initial "DIY CO2" query. I can see that the Aquatic Plant List embodies the best of net-based mutual help! Not only is my air stone bubbling gently, so -- to my surprise -- are some of my plants! Didn't expect to see that after just 24 hours! How long is it likely to be before I see a noticeable increase in plant growth? Thanks again, Dinyar