IMO yes it is. Getting rid of it is half the battle finding out why you got it is the other half. To help rid your tank, syphon out what you can, frequent water changes every 3 days or so, start with a large one, increase flow to the affected areas. And yes even with corals, you can cut your lights down to 3 hours a day for a couple of weeks without hurting anything. I have a tank full of corals, softies, lps and a RBTA. I had to do it and didnt lose a thing in the process. Also, for the first 2 days after the intitial water change, I kept the lights off completley to help kick start things. HTH.