To rule out cyano, you can try chemiclean. Just remove as much as you can and dose as per the instructions. It completely wiped out the cyano in my tank after 2 doses. If all the algae dies, it was cyano.
It does look more like diatoms on the glass though, which is really just manual removal to keep it down. Diatoms are their own kind of algae, and are not cyano. Upping water changes helps to combat it.