Losing encrusting SPS

[Toxic727]

Hi all,

I think I am losing one of my sps! I have had it for over a year and it’s done great until now. I noticed that in recent days it has lost color and I am getting zero polyp extension. My perameters are within target zones:
SG 1.026
Temp 79
Cal 440
Mag 1390
KH 9
N 3ppm
P undetectable.

Attached photo.

The outter edges seems to still have some color. While the rest seems to be dying any advice?

 

[Flippers4pups]

Have you change anything with your lighting?

 

[Toxic727]

No lighting has remained the same for over 8 months. Should I kill the lights for a couple days?

 

[Flippers4pups]

Not yet. Dosing anything? ATO? Where do your returns dump in at in relationship to this coral?

 

[Reefhabit]

What's your pH at? Also do you have any blennies in the tank?

 

[Toxic727]

My returns shoot straight along the top of the water. I do dose kalk through my ato. I do not know my PH. No blennies either. I have an emerald crab that o have seen sitting on the coral but didn’t appear to be harming it.

 

[Flippers4pups]

What other corals do you have near it?

 

[Toxic727]

The closest is a birds nest. Which is rather close but nothing else close

 

[Flippers4pups]

The closest is a birds nest. Which is rather close but nothing else close

Okay, any softies in your tank? Looks like you have some type of coral near by, possible zoa's?

 

[happyhourhero]

Can you test potassium?

Are you using anything to strip p04 that low?

 

[TonyNguyen]

+1 check your potassium levels it's the sign when Monti lose its color they are the first to go.... I dose lugols and pure potassium, and my Monti came back...good luck!

 

[Toxic727]

You know what, I bet potassium is it, but I bet I have too much! I experimented with dosing potassium nitrates a week ago. I Gradually increased to 1ppm