STN in the Middle of Staghorn

[peiloy3196]

I have a blue staghorn that started STNing three days ago in the middle. It started between two branches midway up the colony and is slowly continuing. I cannot figure out what caused it, but a few days ago I had a small dip in Alk because the calcium reactor feed pump stopped. I caught the failure the same day as I test Alk daily. My Alk is normally at 130PPM and dropped to 118PPM. It is now back where it should be. I keep it at 130 because I dose vodka.

Other parameters are:
Calcium: 420 Salifert
Magnesium: 1350 Salifert
Phosphate: 0 Hanna
Nitrate: 0 Salifert

I have never seen STN occur in the middle of the colony as normally it starts at the base or tips. So my question is do you think that this small drift in Alk could have caused the issue?

Other factors to consider.

1) When the calcium pump failed I had to dig around in the sump quite a bit to fix it. So maybe I disturbed something?
2) A week ago I received an Acro that was STNing at the base due to shipping stress. I fragged it and it and the frags have been stable since. Is it possible that this STN on the Acro triggered STN on the Stag?
3) Possibly related to one of the two above this piece is in line with a MP40. Although there are two other large pieces between it and the MP40, maybe something fell between the two branches?

I have about 30 Pieces of various SPS and everything else is fine. I am really wondering what the problem is firstly, and secondly what should I do at this point? Frag or leave it alone?

I have already changed my carbon.

 

[jroovers]

I have been having a similar problem with a large stag of mine, it is recededing slowly at the base however, not in the middle. I think mine was either flow related, or due to increasing low alk and ca parameters, but I'm a bit miffed. I think stags are alk swing sensitive. If the ALK swing is the only thing that has changed in your tank, then that sounds like the culprit. As for fragging, maybe watch closely and then frag if it continues to worsen? I'm going to frag mine likely at the multiple bases, prune to smaller size, and reset with epoxy and hope the situation improves. Can you post a pic?

 

[fcmatt]

Could you have a fish, crab, or some other critter that has taken a liking to eating this
coral?

If it was me I would just keep the tank stable as possible that let the coral try to heal itself.
But I would also plan at what point would I chop up the coral to save some of it before
the STN reached a certain point.

 

[peiloy3196]

Thanks for the response guys. I am not sure if anything is munching on it, but I have not noticed anything when I am looking. I am actually travelling for a week next week so I am going to have to make a decision before I leave on if to let it be or frag.

Here's a pic. Sorry about the crappy phone picture.

 

[jroovers]

That looks more like something is eating it as fcmatt has eluded to.

 

[peiloy3196]

Im not sure what could be eating it though: Fish list:
Yellow Tang
Purple Tang
Powder Blue
Hippo Tang
Red Hawkfish
Royal Gamma
2 X Oc. Clown
Copperband Butterfly
Mandarin

CUC:
Snails & Blue Leg Hermits
I do have a Rogue Black Crab, but his hideout is nowhere near and I have never noticed him remotely close at night.

 

[Allmost]

check the coral closely with magnifying glasses for red bugs as well.

 

[peiloy3196]

check the coral closely with magnifying glasses for red bugs as well.

Thanks for the suggestion. I have done that and cannot see anything. I will look again when I get home to see though.

 

[peiloy3196]

Here are some close up shots. I am not seeing anything other than peeling flesh. Is there something that I am not seeing in the pictures?

 

[hypnoj]

Where it's located at the base of that branch. I'd frag it.

 

[REEF SMAC]

Seems as though something would have to have damaged or irritated it, to have it start there in the middle like that. Like something landed there for a while or was munching on it.

I agree that it might just be a good idea to frag off that branch. Especially if it seems to be spreading.
Cut off that infected part and remount the rest somewhere next to it. It will eventually grow together back into one colony.

 

[Reef_Knight]

Same exact thing is happening to a tri-valeria that was doing very well for the last months.I heard from a scientist that it could definitely be flow constantly hitting it. I moved it hope it recoups.

 

[peiloy3196]

Good Luck. In the end I decided not to Frag and the STN stopped. It looks like it is recovering now. Im still not sure what caused it, but I am glad that it stopped!

 

[Reef_Knight]

I hope the same goes for me I sure love that piece.