lighting a non-CO2 tank

[TomFromStLouis]

I am working out one or two tank concepts in my head. If I wanted to create a relatively fully planted tank (maybe only 2 or 3 species, but fairly densely planted) with absolutely minimal gear (the filterless thread still intrigues me), what wattage would I use? I have read that up to 2wpg is okay for non-CO2 tanks (ie, more begs for injection). Maybe the answer "it depends" on fish load, plant species etc. So maybe I am asking about a top range. Is 2wpg too much, asking for algae?

It sounds like it is time for me to get Walstad's book...

[RTR]

In my tanks I am fine w/CO2 conservation at ~2 - 2 1/2 W/gal., but there is some dependence on species there. Above that level I either need Excel or CO2.