Tom Barr and many others have demonstrated that "CO2 Mist" works better than dissolved CO2 for getting lots and lots of pearling quickly in an aquarium. And, pearling occurs when the plants are growing fast. So, microscopic bubbles of CO2 blown around the tank works better than dissolved CO2 for the plants. But, many of us grew tired of the appearance of the water with those microscopic bubbles everywhere. That, in my opinion, is the trade off - if you don't mind the appearance of the cloud of bubbles, CO2 mist works best. If you don't like that look, 100% dissolved CO2 works best. Of course with CO2 mist you still have a lot of dissolved CO2, so the comparison isn't a good one. I think, but never tried to prove, that the CO2 mist doesn't affect the fish as much as dissolved CO2, so you can run more CO2 with CO2 mist than with just dissolved CO2.
Last edited by Hoppy; 02-06-2010 at 03:41 PM.