I used a green party cfl for a year with no problems, don't know the brand but I got it from home depot. Now I use a green led light hanging shop light and that works well. The brightest I have seen is a green hydro farm 4' fluorescent and it is almost daylight in the room. That's what I'm going to use in my new rooms because I run separate light cycles so one room will be dark when I do my watering.