I bought a zoa colony around 2 months ago. They were all open for about a week and since then about a quarter to half of them stay closed or barely open. I have had aiptasia growing on the frag that just keeps coming back and also these small snail looking things. Other zoas stay open all day long and mushrooms are doing great. Parameters are all fine except alk is a little low at 7.6-7.8. It’s always the same zoa heads that don’t open.