cup coral not opening

[golfdaddy73]

i have a cup coral that hasn't open for about four months, i know this thing is still alive, whats wrong with this thing?

 

[Phyl]

What are your nitrates? My money is on them.

 

[dasstheboss]

try checking the phosphates .. mine closed for a while and when i got a po4 test kit and fixed it.. all went fine!

 

[MauroD]

If it's 4 months in your tank and still alive, odds are it's opening at night... have you eyeballed it with a red light an hour or two after lights out?

M.

 

[JoeV.]

Agreed. Get a flashnight at night after the lights are out for a couple of hours and check to see if polyps extended .. nitrates and phosphate would close this coral
good luck