Bare spot on my birdsnest!! Help!

[AmatuerAuer]

Hi,

I was out of town for 3 days and returned to find a small bare batch near the base of my birdsnest.

Quick frame of reference, the coral is about 5" tall with a few branches. I have had it for months and seen growth. It is located near another birds eat that is/has been doing fine.

The one with the problem had two relatively light/retracted patches on two branches but those have since filled back out and gone through periods of retraction and re-extension.

This problem is not that, the bare patch is bone white bare and also has clearly defined edges making me think it's a pest of some sort that needs immediate attention.

I can take photos later but does this strike a chord with anyone?

Other established tank SPS are doing fine. Some of my SPS frags are experiencing STN but they are new, could have been better acclimated etc so I don't know if they are related. Any advice/ideas/questions are welcome!

 

[TD13]

+1 I have the same sort of thing on mine.

 

[Tahoe61]

Please provide chemistry and lighting. A lot of times an images helps as well.

Take a flash light tonight and look at the coral a couple hours after the lights have been out just to rule out some suspects.

 

[AmatuerAuer]

 

[AmatuerAuer]

Alk 7.8
Mg 1320
Ca 370

Ca is lower than I let it go usually but I wanted to confirm a strange number from yesterday. I began dosing to raise to 450 but am splitting it up to move it more closely.

Lighting is two Kessil 360w one running on a program

 

[AmatuerAuer]

Going to raise Alk after I slowly raise Ca. Usually keep it around 8.5-9

 

[Tahoe61]

Well if you have been having alk swings than that would be my first suspect. It's odd that the area is smack dab between healthy tissue and not STN from base or tips. Keep an eye out for small limpet types, and adjust and maintain an alk target value.

 

[AmatuerAuer]

My thoughts as well on the location.. You think Alk swings could do it??

 

[Tahoe61]

The Acropora in front or next to the Seriatopora looks to be struggling, so I would consider chemistry the most likely cause. But because of location I would for sure keep an out for pest. The other choice would be another coral stinging the Seriatopora but nothing looks that close.

 

[AmatuerAuer]

Had a couple acro frags go through RTN very shortly after delivery. They had not crusted to the plugs and were clearly fresh cut and mailed quickly..

Any idea what I may be looking for at night with the flash light?

 

[Tahoe61]

Limpets or Asterina.