I don't know about restoring color, but we have found that it seems to help with restoring tissue recession. We've brought in several "sick" gonioporas and found that by giving them a reef dip and using a Q-tip with iodine around the infected areas, seemed to help stop the receeding.
Where exactly is your acro placed? Maybe it's getting too much light? Try moving it to a more shaded area.
Getting back to the gonis real quick......we have found that by dosing iron, it helps restore color as well. I cannot speak for other corals, just for the gonis. If you go this route, please get an iron test kit.