This is quite normal and expected with TBS. Not normally too big a deal.Well, my fears were realized when, after putting in a few pieces of "test" corals (few montys, few acros, few zoas) into the tank and getting a call from my wife while I was at work "There is a huge crab eating your coral!!". Over the next few weeks I pulled out over 6 gorilla crabs of varying sizes. I also have a suspicion that a mantis ship is lurking in my tank somewhere (as evident by the slain crabs I keep finding).
But I guess if you are moving over a bunch of old coral it can be a bigger issue.
Never bothered me much though. Especially the mantis. I've had 4 in the tank before. I just pull them out as they get brave and come out looking for food.
But you're right... if it's something that's bothering you, better to take care of it now rather than later when it will be much more difficult.
Maybe i'm nuts but I always liked the click of the pistol shrimps too. haha
Any new pics? I liked how the scape was looking.