Need help and opinions please

So my semi new tank I have had more the my far share of issue on this one
But now I'm out of ideas

I have some Zoas melting
Others turning almost white or clear lps is great and In most cases higher then the Zoas.

only 3 fish
Carpenters wrasse
Hippo tank
Clown

Tank is 84 gal with 2 -10 sumps/refugiums

Refugiums has cheato and 5in special kitty clay litter 1 in fine sand
Flow through the sump is approxmite 300g hour
Reef Octo sro-2000int
2 reactors carbon and gfo

Lighting is
4x80watt t5ho on independent reflectors.
2x blue ati
1x purple ati
1x coral plus ati


Po4 is 0.05
Alk is 8
Ph is 7.78 8am and 8.28 at 8:30pm
nitrates 0
Ammonia 0

I am getting to the point of being over this tank and scraping it and restarting again
Ugh

Any insights ? Please I'm already bald

Pics
The zoa in the middle are purple people eaters.
There clear almost

 

Zoas can be a tricky coral. I have had some thrive while others in the same tank fade and die. I do know that they seem to like water a little on the dirty side. Also lighting requirements can vary depending on the species and color. If they are turning white I would probably lower them and see if that helps. You are running a much stronger light then I had on my 90.Good luck.

 

I have heard that carbon dosing with vitamin C can improve the health of zoas in some cases, along with reducing the amount any phosphates or nitrates. May be worth a shot.