Trachophilia unhappy

[Sequest]

My first coral, a trachophillia, who has been in the tank for about 2 months now has been unhappy for the last 2 weeks.
It has not opened up and its tentacles barely extend very far and not for long.
Last two days I have noticed some sort of slime/residue that came from one of its mouths. And today I noticed some slime underneath it (see photo).
I also noticed the skeleton/calcium part of it is brown with some sort of blotches. I thought it was algae (tank is new, ugly phase is still here).

Any ideas what is going on?
The yellow trachy to the right of it is new. Possibly too close and stinging/doing something to it?
I tried to feed it some mysis yesterday, its tentacles seemed to take some, but with it being so shut up, i couldnt tell if it ate.

He started to become unhappy (wasnt opening up) right after either I did a water change (15%) or added some more corals. Water change was done Saturday, 3 more corals went in Sunday.
Hard to tell the cause. Before this though, it was loving life and opened right up.
Water parameters though look OK, nothing too bad, but i may be wrong.
It is getting about 60-80 par.

Water params:
- 8.2dkH
- 450mg/l Calcium
- 1480mg/l Magnesium
- PH 8.0 (night) to 8.3 (day)
- Salinity: 1.025
- Temperature: 25C


ICP report shows low iodine, and low calcium and mag (but my own tests show the above). I have started dosing calcium, mag and carbonate. But I am not sure i can trust my own tests. I have dosed about 20ml in the past 3 days and both calcium and magnesium results have not really moved at all. No i dont trust my tests one bit.
ICP calcium is 384mg/l
Magnesium is 1150mg/l

Apart from low calcium/mag and iodine, the other parameters are all green in the ICP report.

My only other concern really is with the lack of phosphate and phosphorus. Both are right on the minimum for the setpoint values (P = 6.00ug/l, set point is 6-23ug/l, PO4 is 0.018mg/l, set point is 0.018 - 0.07mg/l)
My nitrates were high, 15 ppm but are now down to around 5ppm. The coral was happy at 15ppm, now unhappy at 5 ppm. Not sure if coincidence or cause.

Finally, there is a torch, hammer, scoly and lobo also in the tank. All of them appear to be fine and happy. I thought the Scoly might be a bit brown in one spot, but i think that might just be my eyes.

Cheers.

 

[Mr. Mojo Rising]

The tank is new, there is a lot changes going on in the water in new tanks that we cant test for. Corals need stability, this is why most people suggest to wait a couple of months before getting corals.

I would suggest to completely stop dosing anything , that is just changing the water parameters even more. Usually we monitor the parameters daily for while to figure out the tanks usage of nutrients, that how we figure out how much we have to dose, we don't just guess.

I think you have gone a little too fast, I would suggest to slow down, let the tank mature a little, get your tank husbandry under control, do more research for success.