If you keep a reef, you really need to be testing , at minimum, Calcium, alkalinity (carbonate hardness), phosphate, pH, nitrate, salinity and temperature.
Acans and mushrooms are two different corals. Mushrooms are much hardier than acans. Yes, both can do well under PC lighting, but this is not the only factor.
What size tank? Where were the acans placed (top, middle or bottom)?
How many watts are the lights?