My plates tenicles on the very edge were starting to disappear and the edge of the rim was losing its color, but my plate appears more flat then yours does, so that might make a difference. I may be wrong, but your plates are not real flat like mine, could be from sitting on an uneven hard surface :notsure: Not sure you could put them back in the sandbed if they would get completely covered, better to leave them where they are if they are staying healthy, thoug i would be concerned about the skeleton warping, becoming mishapen, just keep an eye on them, to pretty to lose because of a wavemaker IMO. As far as lighting goes, I don't think they need real strong lighting, mine was at the bottom of 260 watts of PC.