Hammer Coral wont open after 2 weeks

[pierrelowey]

I bought a hammer coral around 2 weeks ago, when i first put it in it was opened and 'bushy' but 2 weeks on its barely open and i see pieces of it floating in the water column occasionally, any help would be appreciated.
levels are as follows;
9.9ppm nitrates
0.15ppm Phosphates
8.6 dkh
430ppm calcium
1380ppm magnesium
salinity 1.026

my nutrients have changed over the past week as I've tried to get them under control, phosphate was around 0.25ppm a week ago and nitrates were 1ppm. i dosed the nitrates to increase by 1ppm a day and used lanthanum products into a filter roller to reduce phosphates.
picture of coral below;

 

[Uncle99]

Pieces?
Someone in your system tasting it?
Looks like someone nipped it…..

 

[JTP424]

Pieces?
Someone in your system tasting it?

Give us some more information on your tank? Size, occupants (to go along with @Uncle99 and his tasting theory ) , how long has it been running? Does that duncan reach far enough to touch it?

 

[pierrelowey]

Pieces?
Someone in your system tasting it?

it looks like the green tips at the end of the polyps, im not sure any of the fish in the system are coral eaters but could be wrong i have (at the time i saw the issue);
purple tang
2 clown fish
a pair of cleaner shrimp
6 line wrasse

 

[pierrelowey]

Give us some more information on your tank? Size, occupants (to go along with @Uncle99 and his tasting theory ) , how long has it been running? Does that duncan reach far enough to touch it?

The tank size is a 4 ft tank (around 320 litres including sump). it has been set up for around 6/7 months now. the duncan doesnt reach that far, i recently moved the hammer to see if the flow or light was an issue.

 

[Uncle99]

I have a Sailfin tang that ate the polyps from a branching hammer and then just stopped.

Those shrimp can be a menace, they steal food from corals and sometimes are too rough.

Sometimes I think the nip is just a mistake.

 

[pierrelowey]

I have a Sailfin tang that ate the polyps from a branching hammer and then just stopped.

Those shrimp can be a menace, they steal food from corals and sometimes are too rough.

Sometimes I think the nip is just a mistake.

This could be the issue, i had a cleaner shrimp before these 2 (got minced by the wavemaker rip) who was always harassing corals for food scraps but these 2 smaller ones seem to hide all day.

 

[pierrelowey]

All other corals seem to be doing ok