bleached sps

[radreef02]

My pink acro bleached literally overnight. It’s polyps were out and it was fully colored . I wake up to it bleached this morning ? All other SPS have been healthy and good. Even this one but it took a bad trip overnight, I understand the tank is new . But No parameters took a swing. My only thought is too much light and nitrates too low. Can I turn off my skimmer for a few days and see where nitrates go ?

salinity 1.026
PH 8.1
Nitrate 3
alk 9

 

[radreef02]

No alk swing took place. I’m certain it’s low nitrate or the fact that it’s the highest coral in the tank