I have a 10g planted and I'm using 2 13w CFLs for lighting. I think it's a little on the bright side but others say it can be done. I have some Cyanobacteria going on right now. It might be easier using 10w bulbs or something in between, but only "Daylight" or "Full-Spectrum" (6500K). And btw, I think plants use more fertilizer the brighter you go.