Mysterious coral death??

[Red2143]

I have a tank with a number of different corals for around 8 months now. Mysteriously in the past couple weeks the gsp and antheilia have completely died but the hammer, zoa, blasto all seem to be fine. The Duncan only partly opens and the candy cane seems less full. I haven't changed anything.

Salinity 35
Alkalinity 8.3
Nitrate around 5
Phosphate 0 with Hannah ulr

Please help

 

[Dburr1014]

Please post a pic.
0 po4 might do that. Or warfare.