Corals looking a bit rough/ falling off?

I havent done anything different but my son ran up to me and said dad your anenome thing went flying across the tank. I knew it dident sound good. I went in to the room and saw a pulsing xenia booping across the tank. I have a colony of them and there were 2 or 3 that are just bent in half all limp. they 2 candy cane corals look like they are on there way out and the torck also looked deflatted? the xenia was pulsing still but the parameters are good nothing there is off.
Mag 1450 calcium 480 salinity is a tad low at 1.023 nitrites 0 nitrates .05 ammonia 0. I have never seen anything like it. I also notice the coriline has white spots like it has a bit of die off? Its still pink/purple. I also added 2 peperment shrimp but havent seen them. I really dont think they attacked the stuff seems like something is off in the water but what? I have armor of god zoas and they look good the pom poms have what looks like burns on the snowflakes so something it irratating them.

 

What's your alkalinity at?

 

its at 2

 

What is the PH?
Did you recently clean salt creep?

 

8.2

I cant find anything wrong in the parameter standpoint. That is why im baffles. The monti has white spocks like the coriline too its rather odd? Makes no sense. Can a coral of fired off something off something. This is Why I tell my wife to stop buying corals haha. I want fish only she wants huge reef.

 

Yes, from time to time, great mysteries happen in our tanks.....I hate that! Only thing I ever found to help me understand some occurrences was, contamination. Read this;http://www.advancedaquarist.com/issues/june2002/feature.htm

 

Unclejed thanks for the great info.