What's wrong with my branching hammer? W info and parameters

[MuddyPeaks]

Hey everyone hoping for some help to save my first coral

It's not seemed very happy for a while now and I'm really not sure why (have been trying to address it yes, changed spots in the tank and lowered lights bc they were kind of too strong on my 10g)

I'm wondering if this dark spot that I noticed today is an indication of a disease or that it's Dying dying 

Thoughts pls? 

 

Parameters are 

Sal. 1.026

Temp 79

pH 7.8 (it's consistently this low Everytime I test)

Kh 8

Ca 420

Nitrate 20ppm 

 

Other live stock in the tank include 2 clowns, 2tiny hermits, stomatellas and one astrea(? I think) snail 

Bb and this months it's first year's anniversary 

Coral was put in Jan and was doing ok until May, when I moved the tank but nothing else has gotten like this so 🤷🏻‍♂️ 

(My profile picture is how it looked before btw) 

[mcarroll]

Likely to be lack of phosphates.  That's the next thing I'd rule out.  Can you have it tested?

 

If you have elevated nitrate levels, that tends to make their dino's multiply....which naturally increases demand for phoshpates in a number of ways.  If your phosphates are very low, that can be very bad for the coral as it results in unhappy dino's (to put it in a nutshell).