I have the same problem with my moss. It is some type of brown thread algae or hair algae or could be just plain brown algae. Only SAE's seem to want to eat this algae. I tried amanos but I don't think they can handle the growth. I had a bad outbreak in my breeder box including a bad outbreak of green hair algae. I bought 2 juvi SAEs @ 1.5 inches and in one day all the long threads are gone and the box is starting to look better.