Favia dying from the mouth out, huge coral problems with good parameters

[KurtL]

Do you have anything that can rust in your tank?

This crossed my mind that was part of the reason of adding the carbon, but as far as I can tell theres nothing metal in there. Pleasant update that the purple hornets are opening again. The pink colony is opening up more and more every day, and theres some movement with the duncan as well.
Not sure if it was adding the carbon or feeding or both.