I have 25-30 lbs of 6 year old previously live rock

[BlackTracet]

This stuff came out of a long gone tank (my daughter's in college) and has been sitting in a bucket in my garage for 6 years. I can't remember but I think I cleaned it with bleach 6 years ago. It looks clean and very white. Can I add it to my established tank and if so what should i do to it first.

 

[Ron Reefman]

I'd put it in a bucket of fresh saltwater and a small pump. Test ammonia, nitrate and phosphate day 1. Let it run for a few days and test it again. No ammonia, nitrate or phosphate increase, good to go. Otherwise, do whatever you need to do to address whatever issue you find with the tests.