Just about a week prior to my discovery of corals showing signs of issues, I had moved some things around in my tank. Without knowing too much, call it trail and error discovery, I found that certain pieces have serious conditions of placement.
My orange plate was located near a corner of the tank, on the sand. It started to harden up, and didn't look anything like it did weeks prior. In fact, from the time I got it, it would eat weekly and do it quickly. It took about a week after moving it to the corner did I realize something was going wrong.
A point to understand about my setup is that my tank is 36" wide, yet I only have a powercompact that is 30" wide. So there is a difference in my tank based on being directly under the light and not. I placed not only the orange plate out from direct light, but also my green plate. Both took a toll and I have moved them back toward the middle of the tank on the sand and are making excellent recoveries. I moved them about 10 days ago.
Another observation I made was when I moved the orange plate near a large fluorescent mushroom. Within a few days, I noticed the mushroom was getting as large as normal. I researched in the forums to find out that there is a possible mucus that can come off of the orange plates and affect nearby corals. A few days of moving the orange plate away, the mushroom is back to it's large self.
My fox coral is still a mystery. I has not moved, yet there was some macro algea that was growing near it. I believe it was bothering the coral, and I have since removed some of the overgrowth. The coral is starting to appear better, but has not been the same since the altercation about a month ago. I can begin to suspect that the peppermint shrimp I added just over a month ago could also be bothering the fox coral. One of them will hang out upside down on the calcium of the fox. And then once in a while the shrimp will touch the tissue.
I have pretty much lost several violet colored mushrooms. Prior to this, these mushrooms were excellent. They were sharing a rock with some green zoos. They have had their guts out for almost a month now. One thing to consider as well, these were right next to the spot I moved the orange plate to when there wasn't enough lighting. I wonder if the plate created an unpleasant area and these mushrooms took it personally. One of them is still healthy, but the rest seem to be goners.
One benefit that came out of this move was that my chili pepper started to come out to feed. I have had this for months now, and I got it from the LFS
when they had it hanging from the base. So I continued to hang it as well. When I was rearranging from my disaster, I decided to place the base into the sand and lean it up against a rock. Within 2 days I noticed the polyps starting to raise. Then a day later they were out in full stretch. Has been over a week now that my chili has activity.
One last move that I did was I put my brain coral onto a shelf rock from the sand bed. Ever since then, it is even bigger than before. A much better spot, and I enjoy not having 3 sand corals. They were always getting knocked around and pinched by the conch and hermit crabs.
All in all, things are very good again. I am a little concerned about putting anything new in my tank for a while. I have gone with several corals in the last month, so maybe this was a sign of a few things.
Thanks to those that contributed with some feedback while I was going through this.