Just built my first grow box and have had two Meijers brand natural white 42w (150w equiv) CFLs running upside down for 2 nights on my single sprout. Checked this morning and one of the bulbs is not working already!! Are these bulbs made to work upside down? Has anyone else had problems with this size or brand? It looks like pretty much everyone hangs them upside down and i never read of any problems. Thanks in advance.