[Myka]

Is this a FOWLR?

If it is a FOWLR you can do hyposalinity in it for 6 weeks. Keep Prime and a salicylate ammonia test kit on hand in case some of the nitrifying bacteria die (causing ammonia spike). Most of the nitrifying bacteria should survive hyposalinity, but some people do experience significant troubles.

EDIT: Nevermind I see corals in there now. How many corals? Can you remove them for 6 weeks to a temporary tank?