This aglea is beginning to cover my hermits and snails. I've taken a course brush to it, it's doesn't come off of anything. I've delt with gha, Cyano and some other ugliest. But my tank has been super clean for the past month, with only 10% water changes. Only in the past week or so have my inverts started to carry this green color on their shells. I've seen and read that it may be a precursor to coroline but I haven't seeded my tank.