Algae ID

[psiclone]

First things First get some specs out of the way
9 month old tank
skimmer
LED lighting 10 hours a day 8 whites
ph 8.1-8.3
1.025

Got a strange one here that I can't quite nail down. At first it looks like diatoms but it is almost matted down like brown slippery cement. Can dislodge it if you spend 5 minutes on it with a toothbrush. Also can remove with something like a fingernail. Slow growing but spreading. Treated the tank with some chemiclean thinking it may be brown cyano but its having minimal effect at 48 hours. Any ideas?

 

[nautical_nathaniel]

Not quite sure what it is but I would recommend a heavy dose of manual removal. A stiff bristle brush will do wonders on algae like this.