I agree with katrina.
Like you, I needed one of mine to be closer to the light in one of my terrariums (well established and growing in a small plastic net pot) around April of this year. I used 2 neodymium magnets (
MAGNET4LESS-APPLIED MAGNETS-Neodymium Magnets-Rare Earth Magnets-Ceramic Magnets-Industrial Magnets-Magnets Wholesale To The Public). One magnet inside of the pot and the other magnet on the outside glass of my terrarium, which allowed for an easy mount against the back wall.
I have bare glass (with a solid black background), no cork or hygrolon. These magnets are very strong (some have a pull force of 65lbs & 120lbs -
MAGNET4LESS-APPLIED MAGNETS-Neodymium Magnets-Rare Earth Magnets-Ceramic Magnets-Industrial Magnets-Magnets Wholesale To The Public). You can easily break/crack glass if not careful. The thickness of my glass is 3/8". You can not see the magnets in the photo below (for obvious reasons: magnet is inside of the pot and I could not get my camera in back of my terrarium to show the other magnet against the glass), but maybe it will help to show/give you an idea as to what I did.
Also... moving this orchid closer to the light really helped with flower mode.