The tank has 3 wpg and the substrate is a mix of flourite and regular aquarium gravel. Right now I've got some Echinodorus 'rose', anubias, some sort of crypt, and java fern. I had a lily for a few months but it has started disintegrating, and any stem plants I buy tend to fall apart after a few weeks. All the research I've been doing says that with the amount of light I have, I really should be running some CO2. I don't mind investing in a good system because it's my only tank and I'd really like it to be lush and healthy, rather than just an algae farm. DIY CO2 makes me nervous because I'm not sure how to get the mixture right, but it never occurred to me to try a prepackaged fermentation system. Are they expensive?