sen5241b
Reef enthusiast
I had to go back and look at your phosphates to be sure. Phosphates at .5? I seriously doubt your salt has anything to do with the problem. That brain is a stony coral! Dr R. Shimek, one the foremost hobbyist and marine coral experts has said it only takes phosphates at 0.25 to start killing stony corals! I recently had a little spike in my tank and I saw only some stonies start to get bleachy. If some corals look bad and others look okay you can't rule out phosphates as the issue! Deal with your phosphates!