Adding Acanthastrea to an existing tank

[tzylak]

The info card describes Acanthastrea as easy and peaceful, yet warns about conflicts with adjacent creatures. My 50g is already quite full, yet I want to add some orange to the color scheme. Do you have any advice on this addition?
Thanks!!!
Tanks specs:
Fish: Ocellaris Clown, B&W Clown, Firefish Goby, 6-Line Wrasse, Midas Blenny, 3 Banggai Cardinals, Cleaner Shrimp, Fire Shrimp, Banded Coral Shrimp, Peppermint Shrimp, Bristle Worms and CUC.
Reef: 150 lb. Sand, 70 lb. Rock, Frog Spawn, Button Polyps, Hammer, Mushrooms, Kenya Trees, Brain, Leather Toadstool, Cheato and one aiptasia
Tank: 50g hex with overflow, 23 gal sump with DSB, 2x Rio 3100 return pumps, 2x15" power compact 10K, 2x 50/50, 1x actinic, 1x deep blue LED strip, chiller 650, heater 100W, skimmer 65.
I got the tank on 7/18/2014 but it has been established for over 20 years!!
I do semi-weekly water test and weekly 5g changes.
pH 7.8-8.1, NH3 0, NO2 0, NO3 0-3, PO4 0, Ca 360-400, Alk76-8, 77-79F, sg 1.022-25
23 sec. video: https://www.dropbox.com/s/2s5ik52vqmwh4w1/151019 Aquarium.wmv?dl=0

 

[MondoBongo]

it depends on where you put them. they have short tentacles compared to a lot of other corals, mine have never caused problems. their punch is comparatively weak and their reach is very short. in fact, mine are actually losing to a blue mushroom that they're in contact with, and losing even more to my CBB that likes to nibble them. jerk!

did you have a spot picked out for them already?

 

[tzylak]

I have an area designated for them away from all the others.
The specs say that they grow fast and can overtake others. From your description that is not the case.
Thank you for your feedback.
Tom