I was using a dark blue party bulb from WM for a while for my Chondro. The light was blue, but it seemed really bright at night, and it was only 25w. I replaced it with a 60w black light bulb on a rheostat and it's almost completely dark. (I was also able to paint a bad*$$ blacklite reactive acrylic background on black posterboard for him). Are you sure those colored bulbs from WM are ok to use at night, without throwing the day/night cycle off? I think filyered glass would be a lot better to use than just the colored glass on thise party type bulbs.