While muriatic acid is really good at eating off the top layer of the rock it isn't guaranteed to remove everything. After I cooked my rock in M. A. I gave it several baths in plain water and then let the rock sit out to dry for a week. After all this I still needed to go back and blast the rock with a hose and old toothbrush to get all the old algae, polyps, etc... of the rock. If you manually remove the polyps be sure to wear eye, mouth and skin protection. The palytoxin is no joke and you do not want it on/in your body. Hope this helps.