Bubble algae is one of those nuisance algae that can be picked at and picked at, but refuses to go away. Sometimes the bubbles can get quite large and actually damage coral tissue. If you encounter these green bubbles in your aquarium, try to remove them without popping them. Some people believe that popping the algae actually releases spores into the water, making the issue worse. I don’t subscribe to this train of thought, but it’s a possibility that nitrates or other “nutrients” exist within the bubble algae and are released into the water once ruptured. The increasing nutrients could then provide a more suitable environment for more bubble algea or even other types of algae.