Thank you. What do you think could be going on?It does not look like PMD to me either.
I have it placed near the top of my 90 gallon. Am running a six bulb ATI fixture. I’ve had it for 3 months. Originally was getting nipped by a powder blue tang, but I removed the tang 2 months ago. It was lower down in tank but have since moved it up. Perhaps flow is too high? Here are other parameters:
Temp: 77
Alk: 8.3
Ca: 425
Mag: 1300
No3: 40+