Weird stuff on zoas

[sascoaquatics]

I have had these zoas for a couple of weeks now and they have been open every day with no signs of a problem. But it’s come to my attention that they have this weird stuff on them. *they are closed in this photo because the clownfish swap past to close* I have got high nitrates at the moment so I am wondering if it is algae. If it is should I just re dip them

 

[Mr. Mojo Rising]

what weird stuff is on them? Maybe you can draw an arrow on the pic of what we should see?

 

[sascoaquatics]

what weird stuff is on them? Maybe you can draw an arrow on the pic of what we should see?

@LordofCinder