Cyhpastrea Issues

[Preston's_Waters]

Hi everyone, I have been on vacation for a week and a half and I am back to a tank with minor green hair algae and some cyphastrea issues.

I don't know what is happening to them but they don't look happy, also one of my Zoa's has some green hair Algae on it, and the other has not opened in 2 days it has something on it, but I don't know what.

Are they ok? What can I do to help? what am I doing wrong? Should I dose anything?

Parameters:
salinity-1.026
Ammonia: 0
PH: 8.2
Nitrates: 30 (how should I lower this? I already did a water change a couple days ago)
Nitrites: 0
MG: 1800 ppm
CA: 395 ppm
KH: Meq/L: <5.0, dKH: <14.0
PO: 0

Thank you for any help!

 

[Preston's_Waters]

Also the title should have been post vacation issues.

 

[Preston's_Waters]

every so often ill see the zoa try to come out, but only half way and then it closes for a few days, I don't know why and im for sure not an expert on this