Is this STN?

disbelieph · Tuesday at 2:15 AM

Noticed some discoloration on this acro a couple of days ago. During the day when the polyps are extended you can’t even tell. But only when the polyps are retracted e.g. crab walks over it you can see the dark patches of tissue.

When I first got the frag there was one small area of discoloration that eventually colored up.

It’s been encrusting pretty well over the past few weeks after gluing it down. All other acros and sps are doing fine.

The only thing parameter wise that I can think of is my phosphates bottoming out. I only started noticing very tiny black organisms moving on my rock work but not on the actual corals (after reading about black bugs). Not sure if they’re black bugs or just pods. But I ordered a microscope and will try to get a picture.

Params
Temp 78
pH 7.9 - 8.2
NO3 5
PO4 dosed/fed back up to .1
Alk 8.2
Ca 350
Mg 1350

Feeding a mix of flakes, pellets, mysis, and brine 2x a day. Doing a broadcast of Benepets 2x a week.

KrisReef · Tuesday at 8:48 AM

This is not STN. It appears that a sponge or something similar is growing on and over the coral.
Nice picture, but I don't know how to deal with this issue?

wooderbox · Tuesday at 8:53 AM

I am not sure if i am seeing it right without seeing it with higher definition and with the filter but to me it just appears to be shading. I see polyps so it cant be covered in something. Definitely not STN but as the coral grew, some areas are shaded which is normal. The only way to fix is to add more lights like AI blades to minimize any shaded areas.

Troylee · Tuesday at 8:57 AM

Shading..

disbelieph · Tuesday at 9:51 AM

wooderbox said:
I am not sure if i am seeing it right without seeing it with higher definition and with the filter but to me it just appears to be shading. I see polyps so it cant be covered in something. Definitely not STN but as the coral grew, some areas are shaded which is normal. The only way to fix is to add more lights like AI blades to minimize any shaded areas.

This thing is sitting almost directly under 2 bars and an ap9x. Do I need light hitting at another angle?

wooderbox · Tuesday at 9:58 AM

disbelieph said:
This thing is sitting almost directly under 2 bars and an ap9x. Do I need light hitting at another angle?

Only if you want to minimize shading. It will not eliminate your problem because it is inevitable. Personally, I wouldnt do anything because if this coral grows even more, shading only gets worse. You can try to angle your bar lights to see if it improves but if you already have ap9x and 2 bars, so adding more lights would be excessive and i dont want the top of the tank to be fully covered in lights. Dont get too stressed about one coral if everyone else is doing good. Changing one thing for one coral can do harm for others.