Do not bust the bubble if at all possible. It will spread everywhere. Take the rock out, if possible, and tray to pull the bubble off without damaging it. Then rinse the rock in a bucket of tank water before putting back in the tank.
I don't want to start an argument... but I've been waiting for this issue to come up on OhioReef for a while.....and was wondering is anyone actually had any info on this...
What evidence exists that popping them causes them to spread? Bubble algae is a single celled organism, everything that I have found (scientific papers and such) indicate that they reproduce by splitting at the base, and since they are just a single cell, they can split and spread very fast. The natural remedies for this problem (emerald mythrax crabs), end up popping the bubbles when they eat them. And, if they do release spores... wouldn't those spores have to consist of at least one cell? Meaning that a single bubble algae with spores would be a multi-cellular organism? I am by no means a biologist, I've just been very curious about this for a while and have never seen any evidence supporting the "do not pop" stance other than people just saying it on forums.