So I dosed 2 cap fulls of flourish and a few cap fulls of cheato grow in my 160 gallon probably 130 gallons of water volume. Water turned a little cloudy, I turned on a carbon reactor to clear it up. ORP went immediately down when I dosed it and reactor cleared it up a little. Hours later my little blue hippo is dead and my yellow tang is on the verge of death. I separated the yellow tang out and put him in a bucket with fresh saltwater. I'm doing a massive water change. Is there any advice for why this happened or anything else I can do for my tank. All other fish are fine. I do have a powder blue but he seems fine for now. Any help or advice is welcome. I've read iron supplements can hurt tangs???