ich on leather coral??

[fishgardener]

I have tiny white cottony spots covering my leather coral. I'm imagine it is not ich but that what it looks like. The fish are all fine including a royal blue tang. Other coral look well too. Any idea what it is and what do I do to get rid of it.
Ph is 8.1
mag 1400
cal 375 (I know thats low-always a battle)
amm 0
nitrites 0
nitrates 0

 

[fish scales2]

I smell an Alk issue. What is your dkh or alk at?