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

[Canadbis]

I used tweezers and and gently rocked it back and forth until it came off the rock, then I got a few emerald crabs and havent had anymore come back!

[Ruth]

You should probably read the whole article that is liked above and not just parts of it. There are a few theories on how to remove bubble algea but most will tell you to try and remove the entire "bubble" but will also tell you that there is not much of a chance of spreading the problem by accidentally popping the bubble unless you happen to have the perfect storm where the spores are at the exact right time to pollinate (or whatever it is called) and spread.