All my coral closed up and some of them turned white

I had my water tested at my lfs. My dkh and ph were a little low. When I got home I dosed the tank with Aquavitro eight four. Which I have used in the past with excellent results. I also changed out my GFO with some new activated carbon Petco brand.

Long story short my tank was leaking and I switched it out for a new one of the same size.(could not afford a bigger one) Everything was fine until I dosed the Eight Four and changed to carbon. All of my parameters were normal. Ph and DkH were the only things that were off. This is normal for my tank. I often have to buffer.

I only used the activated carbon because my water seemed cloudy since the change. I did a water changed and had my water tested again. Ph was 8.2 and Dkh was 10. I think the Dkh was 7.8 on Saturday.

I think I shocked the coral. So my zoas are all closed up, my monti's are white, my birdsnest is white. Frogspawn is closed up. Also harem of Anthias are fine.

What do I do now? Are my corals dead. Can I revive them. Should I do some water changes. I read to feed the tank, is this correct?

 

Sounds like an alk swing, did you add a lot of buffer? I would look at ca and mag as well, and do research on " 2 part" dosing.

 

I used the recommended dose.
I will look into two part. Are you saying that to fix my current problem or instead of the eight four buffer?

 

if you went from 7.8-10dkh in one day, thats a little extreme. I try not to raise alk by more than 1dkh a day, and most people say 1.4dkh is the max you would want to raise. Changes like that will tick off most hard corals and can cause some to rtn/stn