I believe that it is the same algae that I have been fighting for the last 2 years. It also appears on the substrate.
Increased CO2 levels (pressurised), black outs, Flourish Excel, H2O2 don't touch it. Last Xmas, I did a complete strip down and bleached then boiled everything. All the plants were replaced but it made no difference, the algae was back in 6 weeks!
Having given you the bad news, now for the good news - it appears to be a form of bacteria like BGA, not a true algae. In desperation, I dosed the tanked for 5 days with Maracyn (Erythromycin) and it virtually cleared the tank after the fifth day. It has since come back, so I plan a longer dose to try and rid the tank of this algae for good. I hate using antibiotics, but nothing else appears to work.