Not to hijack your thread, but I think you may have just given a name to what I've been trying to diagnose and treat in my tank. I thought it was diatoms at first, but instead of going away, it just grew thicker.
Is this also bba?
I just took a bunch of decorations out yesterday and scrubbed them all down, and pruned the worst of those leaves.
What causes it, and how do you get rid of it?
Thanks!