Green bubble algae

[PurpleMonkey]

Whenever I see these bad boys pop up, I just siphon them out. I use a piece of rigid airline attached to regular airline. I've cut the end of the rigid on an angle so I can get under the bubble and scrap the holdfast (algae root) off. I turn my pumps off, start a siphon and carefully get them out, just don't pop them.

If you can easily get the rock out, you could carefully use tweezers to pull the off, then rinse the rock off outside the tank before you put back in.