I have an EVO 13.5 MIXED REEF. I have Duncan's, Kenya's, torches, hammers and more. The only corals that I'm having any issues with are my 3 Zoa colonies. For the last few weeks they will only open on a semi rare occasion. All other corals are acting fine. They are all in different parts of the tank, and I haven't seen any nudibranches or spiders on any of them. The coral will still illuminate under the blue light slightly so I know they aren't dead, HELP!!