Soak in coral dip for 5-10 mins a few times a week would help to heal its wounds. With good water condition it should recover unless the injury is serious.
Updates:
Up Aqua F25 LED, no news and unable to contact the guy who reserved it in the first place. Upz...
Beamswork LED200 pending collection tomorrow.
I used to do the same thing as u, adding dechlorinator to tap water for top up and salt water mixing. In the end all my rocks has to be throw away due to the massive algae invasion. Had to spend even more on buying live rock and nsw change.