light per gallon

Question
I need to know if I have enough watts of light per gallon in my aquarium for the plants I have. Right now I have 3.7 watts of light per gallon in my 37 gallon aquarium. The plants I have are, ancharis, anubias coffeefolia, Brazilian swords, penney wort, horn wort and micro sword. Is that enough light?
I was also woundering about CO2 fertilizing. Is it expensive to maintain and do I need it with all my plants? Thanks

Answer
As long as you're talking florescent lighting, that is fine. I usually recommend 2watts/gal for low light, 3-4 for medium, and upwards of 5 for high light. Most of your plants are medium light requiring plants, so you should be ok.
You don't NEED CO2, but it will do wonders for your plant growth. Using a gas tank with a diffuser can be expensive, but it is the easiest most efficient method. There are easier ways...you can use a yeast reactor. Very simply, add some ordinary bakers yeast to a clean 2 liter bottle along with some suger water. Fix the top so that an airline runs into the cap (make sure there is an air-tight seal). Add a check valve, and run the line into the tank, no airstone is necessary. This will produce a bubble every few minutes of pure CO2. You will have to replace the suger every couple of days...when the bubles slow way down. And you'll need to change the yeast culture every month or two. CAUTION, yeast reactors stink! But if you keep it clean, you won't notice under normal operation. They do work, but they're alot of work to maintain. And if you haven't got $300 to spend on a CO2 diffuser, they're good enough. Incidentally, there are other options availible...other CO2 producers use chemical reactions of various kinds to produce CO2 (check out this site   http://www.marinedepot.com/homepage.asp they should sell a few different products). While they all work, none works as well as the tank and the diffuser, in my humbe opinion.
Hope this helps,
Good Luck