Can someone confirm that these tuffs on my koralia are Black Brush Algae. They brushes appear short (1/2cm or so). Pics I have seen usually show this stuff in longer strands. It is more serious in other areas of the tank mostly on filter tubes. It has started to show up on some older plant growth. I try to keep the CO2 at 30ppm, but my Milwaukee regulator seems to have trouble keeping a steady bubble count and I have a tendency to slack and not check on it regularly. Anyway, what is even more strange is that I have been 3x dosing excel for the past half year (for other reasons that BBA) and it doesn't seem to have any effect on it. Maybe it slows its growth, but from what I've read excel should wipe this stuff out. I'm just confused. I'll put up another pic once I get a better cam at home.