i got a rock with some brown zoos, a small feather duster, and two big green zoos about 3-4 months ago. the brown ones all open, but the green ones have never opened up fully since i saw them in the LFS tank. they open half was, but never extend the skirts. i put the rock they are on on the sand, and they open a little more. i have two 150 watt MH and 2 65 watt actinic bulbs 9 inches over the tank ((55 gallon)). Any suggestions?