If it's a hospital tank with no fish and no fish coming in soon. Then no need to cure it. Just simply pour bleach in it and let it run for day or 2 then completely dry the system and let it air dry for 2-3 days.
Then fill it up with saltwater and use dechlorinator as precaution and simply cycle it over again with deli shrimp or for faster cycle use Fritz Turbostart 900 or bio Spria or Dr Tim one and only.