Is this bubble algae?

[Beverly]

Originally Posted by Kabong

Yep that's bubble algea.
If you can get the rock out, pull it out pop it and drain it in to the sink.
Use a course brush to scrub the crap out of the area.
Rinse in some tank water (dont add the water back to the tank)

Have used that method and only had more bubble algae that eventually became a plaque

Here's an article from Christy's Reference Library about Valonia (bubble algae)....

http://www.canreef.com/vbulletin/showthread.php?t=23460

From the article, this is pretty much the method I use to remove it...

My weapon of choice ought to be a small stainless-steel flathead screwdriver, sharpened to wicked excess, and used to gouge out the offenders at the anchorage, even including a thin veneer of rock. Bare fingernails can be unreliable for removing certain 'bubble algae', and can invite injury and infection. I have seen small manicuring scissors, carefully bent in a curve, used to snip off vesicles 'at the root' -but this almost surely leaves the anchorage structure intact, and likely ruptures the vesicle.

HTH