Coral bleaching/loosing skin

[Vamsi]

Hi,
I need help in identifying. My tank is about 2.5 years old. 180 gallon bow front, with a 75 gallon sump.
Two of my corals are loosing skin or possibly bleaching. these two corals had always fast growth. But in the past two days, they seem they are fading away.

My parameters as of this morning
Alk - 8.5
Calc - 450
Mg - 1450
Nitrates around 4.

I dosed Reef energy A&B after I did a 30 gallon water change.

Here are the pics.

Thank you,
Vamsi

 

[happyhourhero]

What is your p04 and how do you manage it?

 

[Vamsi]

What is your p04 and how do you manage it?

just checked with hanna checker - 0.18
Salt - 33 with redsea refractometer

I tried using gfo long time ago and some of the corals bleached, so havent used after that.

 

[happyhourhero]

P04 is fine.

Salt should be 35. That could be the issue or it could be from a swing of some sort. It’s hard to say

 

[Vamsi]

I

P04 is fine.

Salt should be 35. That could be the issue or it could be from a swing of some sort. It’s hard to say

I will try rising it slowly and see if that helps.