No angels in the tank? Only the occupants you listed above?
FWIW, SPS will typically "base out" before they actually start to grow. Meaning, they lay down a very strong base(encrust onto your rockwork) to support the eventual long branches. Also some corals can go dormant for months before actually starting to grow. I've had many acro's do nothing(not even polyp extension) for months, to wake up one day to it being furry and adding skeleton(white tips).
When I first put some of the acros in, two created a small base, but now it's completely stopped.


