Lobophyllia problems

[Vitor]

Running out of ideas. Seems to eat, but tissue receding and white flesh. Everything else is fine, apart from a blastomussa. But on the blasto it is clear to me something is having a bite at it. I think peppermint shrimp, as before it nothing ever nibbled at anything else. But on the lobo doesn’t really look like something is eating it.
What do you think?

Water parameters all as they have ever been, all within what most consider acceptable parameter

 

[Tahoe61]

Type of lighting, duration and intensity? Coral placement with the tank?

 

[Vitor]

Type of lighting, duration and intensity? Coral placement with the tank?

On the sand. Hydra 64 hd. Light intensity little bellow 100 PAR where it is. Light cycle is 12 hours with 2 hour ramp up and 2 dowm

 

[Tahoe61]

What about nitrates and phosphates?
I don't trust any Peppermint shrimp.

 

[Vitor]

What about nitrates and phosphates?
I don't trust any Peppermint shrimp.

5 nitrates 0.05 phosphates
might be the peppermint, but isn't obvious to me that flesh is missing that way. you notice receding, but the first signs were turning white