Been having a problem with some of my sps turning a grey color. Not really turning white like they’re dying but more grey. My phosphates are about .05 and my nitrates are hovering about 30 on the Hanna tester. They’re sitting in about 300 par with Radion WWC schedule light and Orphek bars. I also run GFO and carbon. The flow is four mp40s in the tank and my two xf350 gyres. In terms of alk it normally hovers 8.5-9 range and calc is at 450. Not sure why they would be graying out really