My 20 gallon high aquarium came with the typical all glass hood and 1 15 watt bulb. I changed it to a 10000K bulb to start. (Its a community tank that is slowly getting overrun with plants (I like the look better than fake ones.) I have since learned that I need more lighting (and will be getting a 1x65 compact flourescent when money permits.) I was given a 50/50 cf bulb that runs at 18 watts. I put that on top with my original. Does this give me 33 total watts? Did this help at all? (33 vs 15?) My plants aren't doing so well. The substrate is eco complete. Any suggestions would be appreaciated. Any ideas on DIY would also be great. I have a HOB filter (no powerhead) so I'm having trouble diffusing co2 into the tank. Right now its coming out of an airstone.