I know bubble algae is considered a pest/plague. BUT, when I have had it in the past, I have only had 2 or 3 bubbles in my tank. I eventually pulled them out of the tank, but they stayed there for months without overrunning the ecosystem or anything. I guess I should consider myself lucky, but to be honest I actually found the stuff kind of attractive and hated to see it go (but I knew getting rid of it was the right thing to do!)