light intensity/WPG

I think 3 wpg on a 20 gallon is moderate lighting.

You can get the same results from DIY (fermentation) CO2 as you can with pressurized, but it takes more work and near-constant watching. I have had DIY since I started and have finally found a way to keep a similar amount or CO2 going at a fair consistency, but I have to change out the mixture weekly and output varies with the house temp. If you have the extra money to plunk down on a pressurized system, I'd say do it. If not, you can still have a wonderful planted tank with DIY.

The "difficult" plants are difficult in regards to water quality and being finicky about proper fertilizer ratios. The source of CO2 shouldn't matter as long as you have enough.

-Dave

thanks for the help, so would it be foolish of me to buy plants that require high lighting?

i would agree the 3 wpg would be moderate and pretty close to high, in smaller tanks bc the wpg rule dosen't really apply to smaller tanks. What type of lighting is it?(T-8, T-5...and so on) I think you could get away some high light plants. Some plants dont have to have high light to grow well they just need a lot of light to bring out there various colors or to stay close to the gorund like glosso. You should be fine with most plants depending on what type of lighting you have..

I have T8's and i just bought some stem plants, the ones i was concerned about were rotala wallichii, Ludwigia Peruensis, and stargrass. i would be pretty dissapointed if the wallichii didnt display its bright color