Zoa's issues
 

Hello,

I'm new to Zoa's and yesterday bought my 1st ones from the LFS. both rocks were looking nice and opened in there.

I put them in my tank and the first one is somehow opened but its covered with white/grey stuff like cotton or sponge. what is that and what shall i do?

the other one is a bigger rock with 2 colonies. only half of the rock is opened and the other half is not (which is probably the other type). can you please help !

I'm using LED 4G radions XR15 with an intensity of 50%. the Zoas are placed in the lower part of the tank in low flow areas.

thanks !