Duncan Problem

[BWV1056R]

So I just noticed there are some receded tissue on my duncan but it is still opening regularly. I have no idea what is going on, everything else seems to be ok. In the last pic, the exposed skeleton was probably from my wrasse ripping it off when trying to steal food.
Parameters:
alk: 8.5 dKH
Mg: 1400 ppm
Ca: 400 ppm
NH4: 0 ppm
PO4: 0.025 ppm
NO2: 0 ppm
NO3: 0.2 ppm

 

[DenverSaltyFarm]

Your alk is a bit high for how clean your tank is. With my aquarium being bare bottom and low nutrients I can’t go above 8.3 alk before my tank gets very angry. If you can try to set the alk to 7.8

 

[Mykawl]

Following having same issue, only guess is torch is stinging it or something is eating it.

 

[Mykawl]

Bump