Bubble on acro tip???

[mrpontiac80]

So I have this acro that developed a bubble on a tip between last night and this morning. What is it?? I’ve never seen this before although I’m only about 3 yrs in the hobby.
Side note… I dosed calcium carbonate ( coral snow). Last night for the first time. Following @SunnyX instructions of a teaspoon per 50 gallons. Just figured I’d mention it since it was the last thing I did.

 

[Dburr1014]

You may want to read this.

Post in thread 'Bubbling SPS disease' https://www.reef2reef.com/threads/bubbling-sps-disease.405851/post-11887518

 

[mrpontiac80]

Wow thanks. I’ll have to read through all that. I wonder if I frag that tip off if that would be a good thing to get it out?

 

[Dburr1014]

Wow thanks. I’ll have to read through all that. I wonder if I frag that tip off if that would be a good thing to get it out?

That a possibility. I don't know for sure if the whole colony or is it locally infected.
Not much is known about this.