Your tank may have been set up for 2 years, but it certianly does not look like a healthy established reef.
What is your main filtration system?
I see you list a UV ilter, useless for our reefs.
You have a HOB with a small amount of cheato, whats lighting the cheato, how often are you harvesting it?
With no sump, or other filter, you seem to be relying on the liverock, which it appears you have very little of.
The lighting certianly does not look like its enough. Maybe borrow a par meter and and see what its output really is.
What are your water paramters?
The acro was a wild collected acro, which are very difficult to keep anyway.