I lost a healthy Staghorn Overnight

[Dj City]

I lost my Staghorn overnight.
I've had it for about 6 months and it has been doing great all this time.

I went from this last night at lights out...

To this in the morning...

Needless to say, i'm BLOWN!

I have NO idea what happened or why.

I am keeping a sharp eye on everything else. So far, the stag is the only one that has had this problem.
Well...
it's not a problem anymore because the coral is 100% kaput.

I have just sent out my 1st ATI ICP test for this reef. I need to know what's going on that I can't see with my home tests.
I test everyday with the Neptune Trident. That tests Alk, Cal, and Mag.
I test Nitrate and Phosphate with the ReefBot using Tropic Marin for Nitrate and Red Sea for Phosphate.
Latest tests show 5ppm Nitrate and 0.08 Phosphate
Alk... 8.62
Cal...470
Mag...1410

These numbers for the big 3 fluctuate but not by that much. They usually hover around 8.4 - 9 for Alk, 440 - 475 for Cal and 1380 - 1400 for Mag.

Reef has been up for over a year.
Lights are a reefBreeders Photon 50V2+ along with a ReefBreeders Lumenbar (Hi Octaine) and 1 T5 fixture running a Blue Plus bulb.

Anyone see anything that could be wrong that i'm missing?

 

[X-37B]

Do you have any disco mushrooms in your tank?
If they let go and land on your acro they will cause stn or worse.
Ask me how I know.

 

[Dj City]

Do you have any disco mushrooms in your tank?
If they let go and land on your acro they will cause stn or worse.
Ask me how I know.

No mushrooms at all.

 

[X-37B]

I looked at your build thread.
Do you still have the long spine urchin?
I had to remove mine.
It killed a couple of acros.
I found it chewing on them.
Emerald crabs were removed for the same thing.

 

[Dj City]

I still have the very long spine urchin.
I've been thinking about getting rid of him simply because he's gotten too big.
He's honestly too big for the 180 gallon reef.

I have 2 emerald crabs but I've never caught them munching on corals.

 

[X-37B]

I still have the very long spine urchin.
I've been thinking about getting rid of him simply because he's gotten too big.
He's honestly too big for the 180 gallon reef.

I have 2 emerald crabs but I've never caught them munching on corals.

Check the emeralds at night.
You may be surprised at where they are.
Thats how I caught mine.

 

[TheDragonsReef]

Did your temp spike at all the last few days?

 

[Uncle99]

Sometimes, they just let go....had this happen several times over the years, not sure why, just very unforgiving.

Sorry for your loss, looked like a great piece.

 

[Skynyrd Fish]

My long spine has turned to acros also. New for him in the last month.

 

[monkeyCmonkeyDo]

Mine was the size of a small basketball. Lol. It was time.
Is your heater still working? Sorry for your loss.
D

 

[blasterman]

When emeralds or crabs attack SPS they remove chunks or stripes. They dont just wipe an acro this size clean.