SPS Bleached

[Aquattro]

If you can remove it from the tank, smell it. If it has that acro smell, it's still alive and can come back. I've had frags go completely white for months, then suddenly color up.
Alk is also not likely the issue, I run a really low nutrient (as opposed to nutriment?) tank with alk around 14 (not on purpose, it just likes to sit that high). I don't have any bleached acros.
As others have said, sometimes frags just do this just to be annoying. You could add a second frag right beside it that does fine. Grab a couple of test frags from someone and see what happens. If they bleach too, then look for a problem. But don't get all worked up over one frag, it's probably just bad luck.
Low Ca will inhibit growth, but not likely to bleach a frag. Best guess on this one was just stress of moving. If it still has tissue (you'll smell it), then it's got a good chance to recover.