What could be happening to this frag?

StikHedRon · Apr 21, 2014

I am concerned about this frag I got about 6 months ago, all my other acro frags and colonies all look great and don't show any visible tissue issues like this one does. I have carefully inspected all my acros the best I can from the front glass and side panes to see if there are any bite marks on any of my acros from AEFW, I have not seen any. This is the only coral in my tank that looks like this. Any help would be greatly appreciated. I do not notice bite marks on this coral just flesh is missing in certain areas. The polyps are out and the coral seems happy, it's encrusting well, hasn't colored up to it's potential but I have it in about 250 par level in the tank. My parameters are:

CAL - 410
Alk - 7.5 dkh
Mag - 1500 a bit high as I was just battling bryopsis so that's coming down slowly but surely
Nitrates - 0 on red sea test kit
PO4 - Usually .01-.02 sometimes it will get to .03-.04, checked on Hanna HI736
Temp - 77-79 2 degree fluctuation during the day
Lighting - 3 250W 14k and 4 39W T5
Light period - T5's on from 10am-10pm MH on from 1pm-7pm
I do run ROX 0.8 and Phosguard and I also Vinegar dose (just started) at 25ml per day

My apologies for the sideways photo.

evolved · Apr 21, 2014

How much flow does it have in that spot? Too much or too little might do this.

StikHedRon · Apr 21, 2014

It's not getting beat with flow, maybe closer to the medium lower flow?

StikHedRon · Apr 22, 2014

No other ideas besides flow? Come on experts help me out here!

gdemos · Apr 22, 2014

too many scenarios are possible to just state reasons why you are lacking color on this one piece alone. taking your statements we can only assume that the Alk at 7.5dKh (pretty low) has been consistent along with your Ca at 410 (good but kind of low).
it may be that this particular piece is stressed, showing tissue loss/poor color because it is more susceptible to the lower alk than your other pieces.
did you dip?
what is maintaining your alk/Ca other than water changes?
how is your fish bioload?
did the piece have good color etc under your care prior to this pic?

assuming you are keeping these measures stable I would suggest starting with a cut back in your photo period in hopes of giving some repair time.

other than this and despite all good care sometimes we lose pieces.