I dip mine periodically in Lugol's Solution. Look for these directions on RC with a search for Zoa Dip. I always dip all new zoas. Also, if you have lots of pods in your tank, they will crawl on the zoas and make them close. I had to get a 6 line wrasse for my frag tank to eat the pods. Closely examine them for nudis. Look up a pic on reefcentral so you will know what you are looking for and if you find them (may see them crawling on your glass too) follow the directions for the Lugol's dip. Good luck.