Check the heads first; disconnect one and check for the noise then swap and do the same. Might seem coming from inside.
I had a small patch of bubble algae and tried my best to remove it without rupturing any of the bubbles. I think I only removed a couple successfully that way. All the rest popped. I didn’t see any new patches though. I guess I may have just lucked out though.Interesting read. I recall @Thales saying he didn’t believe they would release spores when smashed. Must depend on type I guess. The article does point out it’s not a given that any released spores will successfully grow into new bubbles, and they will release spores eventually if not removed or smashed anyways. So it seems you have little to lose if you smash some during removal. I also feel that it will encourage animals to eat them when they’ve been ruptured.