I received 52 lbs. of Fiji live rock today. The instructions on the box says to add to tank and start the cycling process. My question is do I need to cure this or quarantine it for three weeks in a vat of salt water at 82 degrees for three weeks?
If you received the rock from an established tank and have it in buckets in water than you can add it to your tank and just keep an eye on levels.
If you got it in the mail or it's been otherwise out of water, it will need to be cured. If you have (1) a brand new tank build you can cure it right in the tank. If (2) you're adding it to an already established tank, you should cure it in a barrel until ammonia and nitrites go up and then back down to zero-ish before putting it in your tank.
You can cure it at room temperature, above 70 degrees.