ohh now i get it. well i think during the day. since much of the soft coral full tem self with water and during the day they feed and for shure they will "strech" and be a little bit bigger the next day. and LPS well you can tell that during the day there polyps are out, but they grow 24/7 and you can tell by looking at the tip of the, specially acros. if the tip is white that means healthy and growing.