sidetracking a bit here, but to clean the nasty dark green algae off my anubias, I swiped the leaves with some cotton dipped in 5% rubbing alcohol and the algae came off pretty clean, the leaves are doing fine, no signs of injury due to the alcohol. scrub lightly though, you dont need that much elbow grease with the rubbing alcohol. Also, be sure to wash the leaves under cold running water to get the glycerin residue off the leaves.