Test for phosphates and nitrates and back off on feeding. Are you using live phytoplankton? It can cause film algae blooms. Are you using any filter media that perhaps is'nt getting cleaned out? Are you doing weekly water changes with RO/DI water? How many fish and how much of a clean up crew do you have? It is normal to have to clean the glass every day or so, unless it is bright green and blooming out heavily every day.