Hi Twicklund,
Welcome to the board! My three *small* tubes came preattached to a flat lr. I put the lr on the substrate several weeks ago. Over the last few days, one of the the scarlet reef hermits I have ate them up. So you might consider putting them in a lr crevass if you can find a suitable one (although this won't protect them completely). Also, a crevass usually gets more current than on the substrate--another reason to put them there.
sam