Ok i have my grow room set up to where i have a shop light with flouros and some cfls...what would be best to use for reflections if i cant paint walls off wht...could i use a mirror or poster boards?
Mirrors absorb light so that's a no go. Mylar is about the best you can get. You can get rolls off ebay fairly cheap.
Not off-white, white. Flat, bright white. Why can't you paint the walls? As an alternative, get some pieces of cardboard, paint them white, and set them up around the grow area.