Try an old credit card or - very carefully and stay away from the silicone - a single edge razor blade. If you have plain Mr. Clean sponges around then they work wonderfully as well.
I don't have this particular algae now that I dose phosphate. I suspect phosphate makes it easier for the snails and otos to eat is all.
Less light might help, not more.
thanks for the info I will see if I can scrape it off. I would like to fix what ever is causing it so it doesent come back