"Lettuce" dying ?

[Nautical]

has a "lettuce" coral for two weeks. honestly, neither i nor the lfs has the real name. can anyone identify for me. see pic at bottom left corner.

more importantly, today, within 24 hours, the brown colour starts receding leaving only the white skeleton. see second pic for a close up.

i know it must be a gone case liao. will have it removed and thrown away unless someone tells me there is hope by tomorrow.

can someone educate me on what has happened, i.e. the name and nature of the "disease".

what are the probable causes ?

btw, 1st pic to show general health of tank. 2nd pic is close up of "lettuce".

i have not tested water parameters for the last one week, but hope the 1st pic gives a general indication.

[Nautical]

1st pic

[Nautical]

2nd pic

[FuEl]

The pic a little blur but it looks like merulina.

[Nautical]

oops, sorry, picture is at bottom right (not left) corner.

texture of coral is hard but very brittle.

[Nautical]

can someone give advice ?

[jsoon]

I think the corals has already been subjected to chemical prior to your purchase. There is nothing much we can do...

[dradttg]

Looks like a foxy to me.

If it is foxy, try to shift it somewhere that is not directly under the light and low current.