Bubble algae could and will grow even in water with good parameters. I did have this problem too in the past. Emerald crab would be a good choice, but I had to get rid of mine because it was eating my coraline algae and sometimes picking on my corals. You really can't just squeez them in your tank because this will release spores and cause them to settle and grow all over your rocks. It was pain in the butt, but I had to take most of my rocks out and scrape them off with toothbrush and rinse. I've seen many people do well with emerald crabs though. Goodluck.