Ernie, "Millepora" as in Milleporina (hydrozoan fire "coral"), or as in Acropora millepora?
For M. capricornis and P. damicornis, if intense light, strong water movement, and optimal values (as in natural seawater) of Calcium, alkalinity, pH, etc. are maintained, these animals have no problem thriving vigorously in captive reef environments. Be sure, that if you get to visually select what you buy, look for a healthy specimen: no active recession, etc.
Chris