I'm having the exact same issue with my anubias and I'm glad to see this thread. I've got about 25-30 plants in various places around my 75G and they're covered in a combination of green and black spot algae. The black seems to be around the edges of the leaves with the green in the middle. New leaves come out green and clean but it doesn't take long before they're covered in the stuff. The leaves look horrible. Ironically I have NONE of the algae on my glass where I usually have this kind of problem.

I'm currently running 2xT8 6500K fluorescent bulbs on ~10 hours a day and do a 30% water change weekly. Next time I get a chance I will definitely try spraying them down with peroxide and reducing the light time down a bit.

What % peroxide are you using? I think there are 2 or 3 different %s available at the store.