aluminum cans will most likely bounce the light back and forth in the can, and any that can get out will shine straight down, and not out at a cone shape that is desired. Just look at how reflectors are designed, and make something like that out of thin sheet metal or mylar covered plywood or something. Just 1/4" plywood painted flat white would do a good job.

Show me the plastic tubs you speak of.
Opie Yutts Reviewed by Opie Yutts on . CFL Light Intensity Question... Does anyone know the optimum positioning of a CFL. What I mean is, does a CFL's light intensity radiate parallel to the bulb (inline with the coil) or perpendicular to the coil. I don't know exactly how to explain my question, but I do not know if I should align my bulbs so that they point at my plants, downward vertically, or if they should be aligned so that they point outward, horizontally. Does anyone know ? Rating: 5