As long as the T-8 bulb is 6500K or more, it will work for plants. This bulb can either be made especially for aquariums (more expensive) or purchased at the hardware store for regular fixtures (cheaper). I have not noticed a difference between the two, and I honestly don't think there is one unless your dealing with a high light, high tech tank.
You can go by the watts per gallon rule: 1-2 watts per gallon for low light plants, 2-3 watts for medium light plants. I know that the watts per gallon rule is considered out-dated, but for the life of me I can't figure out PAR (the new measure for planted tanks) and God bless you if you can.
Last edited by Perseusmom; 04-29-2013 at 03:46 PM.