Hello! I have a couple zoas that have been looking weird lately. I moved all of my zoas from my main tank, to a new frag tank with different lights. Tank is cycled, though it’s only inverts atm so I’ve been feeding them. Likely not enough nitrates. They all opened after a couple days of the transfer, though a couple of them don’t look to hot. The polyps stay closed and are covered in a brown film. Anyone know what I can do about this, or how to prevent it? Thanks for anyone who can help!