Zoe's and algae help
 

i have a few high end zoo's that were nice and open and now there closed, some seem to have this algae growing on them preventing them from opening up, what causes them to melt away too, i also have seen this happen, any thoughts

Does it look like bryopsis? Have a good search and see if that's what it is. It's a common algae that infects coral frags, and can be addressed by increasing your WC regiment and by dosing magnesium to slightly elevated levels!

If it is Byprosis you can treat the individual frags with a mixture of 50/50 tank water and hydrogren peroxide. I had this only on a few Zoas i picked up and treated it this way. After two treatments there is no more byprosis and they have began growing again.

I dipped them for 3-5 mins then rinsed them off really well and then returned them to my tank. While being dipped I swished them back and forth to get rid of any loose Byprosis.