As psuedo said, buy some snails and invest in a mag float (magnet cleaner) . Everyone gets green film on their glass. I have to clean mine about once every 3 days, sometimes more often.
Is your tank a new setup? If so, you may see more film algae than usual, but it will slow down in time. Using RO/DI water will help, as well as keeping nutrients low by feeding less.
I think your just seeing normal film algae though... everyone gets it
Cheers.