Sarcophyton leather closed with brown mucus?

[fishjelly]

We recently noticed our Devil's Hand leather has developed some irritated/pale tips and what appears to be brown slime accumulating on the "fingers" (please see attached photos).


Water parameters:
180 gallon
pH: 8.2
water temp: 78 degrees F
kH: 7
Ca: 380ppm
Nitrate: ~2ppm
Phosphate: 0.03ppm
Salinity: 1.026


This leather has been in the tank for over a year now and we've never seen this brown mucus before or the pale bruised tips.


I've recently changed the GFO/Carbon reactor which caused a drop in phosphate from 0.2ppm to 0.03ppm.


There are two other leathers in the tank that have full polyp extension but a couple of the polyps appear to be spitting out some zoox.


Out of curiosity, we suctioned out some of the brown slime and placed it under our scope. Are the brown organisms in the slide zooxanthellae, diatoms, or something else?


Other reef keepers have suggested dipping the leather, but I don't want to move it in case it gets stressed further.

 

[fishjelly]

Here are additional images of the micro organisms. Many of them were still moving around on the slide, though they do not appear to have cilia or other visible motile parts.