As I believe your tank is fairly new, it is best to cure it before you add it to the tank so you do not get an ammonia spike from the die-off on/in the rock.
You can cure it in the bucket, first rinse well with rodi water, then fill bucket with new SW add a powerhead and a heater and let it sit there until it doesn't smell bad anymore, it might take a few weeks.
If your tank is not new...and you have a large, more established (over 1 year) tank, you might be able to cure it directly in the sump if you scrub it clean, but you would still need to watch for an ammonia spike.