Oh okay, great. I would probably do a hyposalinity treatment to the fish in that tank. Over the next few days though, you want to slowly take out the live rock. I would take out a pound or two each day. This way, you don't cause an ammonia spike. To be on the safe side, you may even want to pick up a bottle of Turbo Start to ensure that your ammonia does not spike while you are removing the live rock.
What is the pH and kH of this tank? Do you know?
Beth has a great thread at the top of this forum explaining the proper way to do hyposalinity. I would suggest you read that as well.