Pulsing Xenia question

Hey guys
I have a big colony of purple xenia that when doing well is huge, purple and pulsing like mad.

Every now and then however, seemingly completely out of nowhere, the xenia will close its tips, start to recede, and turn completely white...

I have had this happen at random times and do not understand it. The rest of my tank looks fine.

Specifically, can someone comment on things that Xenia is so exquisitely sensitive to?

 

I don't think there is a major issue as long as it returns to normal after a few days. Soft corals do this from time to time. Can you clarify if the coral returns to normal?

 

It does typically return to normal after it does this...but it must be something in the water because I have two completely separate colonies and they do it at the identical time.

Also when it happens I do a 20% WC, clean my filter floss, and just let my skimmer skim very liquid...after about a week the coral recovers...

But no other corals are affected and things test ok so I have no idea why it happens but the course is identical every time....

 

Try monitoring your pH during the time the Xenia seems unhappy and then again when the Xenia perks up. I have found with my Xenia if they looked wilted raising the pH usually helped.

 

Plus 1. My green star polyps are the first coral to show any sign of swings in my reef tank.

 

What other types of coral do you have, and do you run carbon? Many corals release toxins to protect their turf; in a closed environment, this can irritate or even kill sensitive tankmates. Carbon will remove those toxins before they can cause harm.

 

Yep I run carbon. High quality stuff too. I change it every couple of weeks.

Other corals:
3 headed torch
The xenia colony
Blue maxima clam
BTA
Coco worm
Feather duster
Hammers
Maxi mini carpet anemone
Finger leather
Candy canes
Long and short tentacle plate
small zoa frag, small mushroom frag