HELP! Coral Not Opening

[Dbullis]

Hey everyone, I am still new to the hobby and have a 90gal cube reef tank, I have a green star polyp that came with the tank setup when i purchased it, it has been do amazing and spreading like a weed.

Last weekend I got a few new corals, I QT'd them and dipped them before acclimating to my DT. One of the corals I got is a Devils hand, it has been opening wide and full everyday at lights on and closing at night. Thursday night it closed and hasn't reopened (36 hours). Now this morning my GSP main colony hasn't opened a single polyp but the frags and other spots in the tank where the GSP started to gorw are all open. I'm curious why these 2 corals are not opening. Any help would be appreciated.

no color changed noted on the corals. other corals seem happy

JUST tested my parameters and are as follows:
PHOSPHATE (PO4) 0
CALCIUM (CA) 480
NITRATE (NO3) 0.1
NITRITE (NO2) 0.1
AMMONIA (NH3/NH4) 0
PH 8.2
TEMPERATURE 26.6c
SALINITY 1.025 - 1.025

 

[sailoracu2]

What is your Alkalinity

Sent from my SM-N920V using Tapatalk

 

[syrinx]

break out the calculator he gave you Ca and Ph

 

[newlights]

Were the phosphates 0 before? Not sure about these specific corals but i have heard of corals that like a small bit of phosphate.

Sent from my SM-G935V using Tapatalk

 

[OoooDRAGONoooo]

break out the calculator he gave you Ca and Ph

Ok,I will bite,how can you work out the kh by only knowing the calcium and ph readings?

 

[Agostinone]

The leather corals I've had go through cycles where they don't extend their polyps for days at a time. I had read that they tend to do that when going through growth spurts. In my case the leathers were toadstools though I assume a devils hand would be similar.

Maybe it's just a coincidence that you GSP are withdrawn at the same time.