Acans and brain corals closed up

[Jim jardes]

Salt 10.26 ph 8.3 ammonia 0.0 nitrites0.0 nitrates 5ppm alk 8.4 cal 410 mag 1600 first two were july 16th last two pictures July 31st.
Not sure why the brains are dying, the acans also are not doing well and I can not understand why this started happening in the last two weeks.

 

[james30ct]

What lighting and fish do you have?

 

[Jim jardes]

Chinese knock offs lights sailfin tang purple tang ,square ant, fire fish,two harmless clowns ,3 dragnets and a huge clean up crew about 60 of them all the other soft ,Lps, Sps corals look great and growing this has happen in two week tank temp is 78to 79 one day it hit 81 with the humidity

 

[chevy4w]

Your mag is 1600? A little high, no?