Saw this a little late, but the way I do it is take a square clear container, have clean salt water for water change then take water from display and put into the container this is for rinsing. Than take infested rock out of the tank and go outside on concrete and take a scalple knife and scrape all zoa off using goggles, then rinse in container using a blue light to check for more. After removing all zoa and rinsing by twisting rock in hand, then add rock back into tank. Done