I had read this and have been thinking about it every since,,, I have lots of acans in my tank,, have them mounted to my rock like you would mount sps corals in your tank,,, I am no expert,, I had/have the same problems that you are having,,, I am learning as I go with these corals,,, my tank parameters are pretty much the same as yours,,, calcium is in the 500 range,,, its not that I dose calcium,, its staying at that number from just water changes,,,
I feed my corals Fauna Marin LPS pellets once or twice a week,,, they love the stuff,,, so its not a food thing,,, I think its just a light thing ,,, not enough of it,,, the acans I have no trouble with are the ones higher up on my rock scape that are getting the most light,,, I have yet to bring any of my problem acans back to their full glory once they started to go down hill,,, they haven't died,,, but they aren't making a come back either,,,
I have been raising my LED light percentages up a few points at a time,,, am hoping the problem acans will make a move to getting back to where they are happy again,,, at the very least,,, I can watch the other acans and see if the higher light will stop any of the other acans from going down this road,,,