Dude-
IMHO, attempting to ID acros (and most other SPS for that matter) is really rather pointless. You're taking a small piece of coral, and subjecting it to totally different lighting, feeding, and current regimes than it would normally experience in the wild. This will cause it to express different morphology, color, etc. And after all of this, you're trying to ID it with only one small portion of the original specimen. To top it off, you'll then be adding it to a tank that may have a 3rd different set of conditions. Best thing you can really do is look at hte pic, compare it to others you already have (or want), and hope for the best.