I went and bought a CO2 ladder (bubble counter) made by Nutrafin (Hagen) and set up a DIY CO2 reactor for my 15 gallon tank and the plants grow like crazy!
I set it up with some tubing to a 500ml water bottle (drilled a hole in the top and siliconed the tubing in about 1.5 inches into the cap). Then I fill the bottle about half full of water, put in about 1/4c of sugar, 1/4 tsp of yeast and 1/4 tsp of baking soda. Put the lid on and you're ready to go. It takes a few hours for it to start up and lasts about a week and a half before you have to dump it and make new. I'm sure there are better recipes out there but this one works for me. I have it sitting on my light strip to keep the solution warm and the yeast happy.
You should be able to find it at most pet stores that sell fish stuff
also:
www.plantedtank.net great for info!
Christy
