Yes it will be safe to use. I bought a bunch of Tx holey rock from a quarry. It was REALLY dirty. But cheap and has some great shapes to work with. I hosed it for like an hr hitting the holes until the water ran clear, then put it in a new trash can with some bleach over night then hosed it good again, resoaked it over night in clear RO water, and it was fine, Been in my tank for almost a yr.