Ok here is a plan of attack take rock out of tank one at a time remove bubbles. ff they break or not take a suringe of boiling water and spay the area the bubble was on. This way it will not come back on that area of rock you only loss the area of rock that you spray with the boiling water. Look at it this way you will be sure that you got it and it bactieria and coriline algea will come back. I do this for a number of things. Atapsia, halmeadia algea atleast some of it the stuff that is like disks is alright, but the stuff that is like thick hair grows way to fast and realy thick.

Bill