The zoanthid problem... (Zoas not fully opening, only their mouth can be seen)

[Katze]

Hello everyone !

I purchesed 3 zoa frags each from a different place, about 6 months ago.
During summer after changinge my light, adding a torch, having cyano, and temperature +26C for a week, then a month later none opened not one head ! Mind you that I had to decrease flow because of my torch.
I bought a 4th frag 1-2 months ago, which has 1 head with 2 smaller ones and that opens up very well.

Details:
Params 2 months ago:
NO3 100
PO4 0.00 (rarely) - 0.04
Mg 1350
Ca 460
Kh 8.6
Nowadays
NO3 <25
PO4 0.00 - 0.04
Mg 1350
Ca 460
Kh 8.6
Tank is 1.5 yrs old
Livestock: 5 fish not one coral muncher, no CUC.

Question is that what could cause them still being closed ?

 

[coralnutz]

How's the mat of the zoas look? Solid or like pealing off? Got a picture?

 

[hexcolor reef]

what's par are the zoathids getting? you may have to move them closer to higher flow and lower PAR. area

 

[Katze]

what's par are the zoathids getting? you may have to move them closer to higher flow and lower PAR. area

Par is around 130-150 at max where they are at.

How's the mat of the zoas look? Solid or like pealing off? Got a picture?

They are solid but they shed like leathers would, atleast sometimes they do.

 

[Katze]

They are solid but they shed like leathers would, atleast sometimes they do.

And sometimes they open so they can fit their mouths through and grab scraps of food or something like that but that's all about their activity.