Monti's and other SPS darkening

[c_ronius]

They seem to be surrounded by stingers... Constant stress can make them lose color.

 

[radfly]

I've been fighting this on-again, off-again problem for the last ~6 months.

My Monti's are the first to show it and then the other corals in my tank follow:

The color/tissue will start turning black over the course of weeks. I don't have any filters for my phone camera, so I apologize for the quality here:


This Red Monti, when doing well, is pure red throughout the coral (how it looks on the tips in this pic is how it looks throughout the entire coral, not just on the tips).

Here it almost looks like shading, but it's just darkened significantly in the core of the coral.

Here's another coral, which is usually a bright orange with some bright green polyps. The tissue is almost black/dark brown and the green polyps still show throughout. A little bit of bright orange still exists on the outside.

Parameters have generally stayed around:
8.2 Alk
450 Calc
1400 Mag
79-79.5 F
34-35 Salinity
Nitrate 5-10
Phos: 0.04-.10 (when it hits 1.0, I hit it with some phos RX to get it back down)


The monti's have fluctuated where they'll darken like this and then bounce back slowly and then fade off again. I've tried various things (water changes, feeding more/less, carbon changeouts etc), but haven't been able to identify the cause/solution.

Other SPS corals not pictured have generally turned and stayed greener than they used to be for the better part of the last ~6 months. My best colony SPS the tips 'died ~3 months ago and now has some kind of algae growing on just the tips, though the rest of the colony looks totally normal.

I've never experienced this specific problem in my ~9 years, but this year it has been a problem that I can't seem to properly diagnose and treat. Any help would be super appreciated!

Any updates? My monti and some sps doing the same thing. PAR has not changed on a year… nitrate to phosphate ratio 1-150, salinity 35 ppm, temp 78.

 

[Stevorino]

Sorry to report that I never figured it out.

I was a month into planning my tank upgrade when I posted this and eventually just gave up knowing a new tank was months away. I hate to speculate more since I didn't see it through