Why my sps coral is not open up?

[X.M.Chen]

my sps coral is not open up. But it did have some growth. I have a new coral that is happy when I received it and when I put it in to my tank two week later they stopped open up. Why? Can someone help me or explain to me?

I have 125 gallon tank that is 1 and 1/2 years old.
1.025
Ph 7.86-8.06
Cal 460
Alk 8.6
H3N4: 0

 

[Salty1962]

What kind of coral is it? Sometimes coral PE doesn't occur during the daylight hours. In the wild they only open up during the evening to protect their polyps and due to that being the period during which phytoplankton is prevalent. If you don't have daylight PE, check it out at night to see if it opens up. I don't get much PE during the day either. That's why I feed at night when PE is the greatest.