You want to use a full spectrum fluorescent lamp as a night lamp? That's obviously not going to work for you, since you'll be taking away their night. They need darkness at night and a bright lamp won't give them that. If you already tried a subtle nightglo and that was enough to disturb them, you're probably not going to find a lamp that's subtle enough to not disturb them. This is a nocturnal species which thrives in completely dark, so provide them with that.