oh also. my grow space is 21" x 16" x 26"(LxWxH) and I have total of 400w of light(4x26w cfl's). I think the fact that my grow space is so small plus being in a small box wrapped with aluminum foil actually makes the small amount of lights I'm using work just fine. it is super bright inside and every plant has a cfl directly above it and to the side of it within 2 inches.