I'm not reall sure how old it is, but I just got it a few weeks ago from another reefer on this forum (so I voted a year or less). Its a crocea, and its about 4-5 inches. I have it under 250w MHs at about 16" of depth on the rock work. I have not fed it directly, it just gets leftovers (looking great so far). Water parameters as of today:

CA - 420
Alk - 7.7 (a bit lower than normal)
MG - 1290
PH - 8.22
SG 1.026
Temp - 80.1
NO3 - 0.5
PO4 - 0