bubbleponic res question

cant seem to find an answer anywhere, i know i need to stop light from getting in my res' but do i paint it black, or white? or do i do a coat of white then black on top of that or vice versa?

Major Toke made a post on this in one of his thread's. He used a plastic like you would use to water proof electrical connections. I think it was when he was building his system. VV