Ever thought about it that some is green algae and some are bacteria!!
I would just take the task and clean it everyday, how much trouble is that?
It's like brushing your teeth everyday and your tank needs to have the glass cleaned everyday.
It's also a indication as if you don't have any on your glass one day, than you know your nutrients in the system are low or too low.
Test for Po4 and No3 few days in a row.