Looks like something is stinging it? What is that in the bottom surrounding it? Macro algae? Aiptasia? Polyps? Is that a frogspawn need to it?
probably from the aiptasia stinging it.
Looks like rtn how is your flow?
its seems like a monti digitata with RTN
was having the same problem and i just change them to another place with less flow, try it and if the RTN continiue you will need to frag them to stop it
Your alk is 7? has it been steady there for a while? Alk swings can do funny things, usually bad.
Hmm... Funny that you say that - I did add the WP-25 just last week. However, this happened overnight. Would you say it could be the flow?