I would try some hyacinth, lettuce, hornwort, maybe some reeds (more of a 'grassy' type plant). The more water surface that is covered, the less sunlight that gets in to cause algae problems. I've read that uv filters can help, but I've never tried one.
I usually (like now) have a slight algae build up until I can get some lettuce and hyacinth to cover the surface. Shortly after, the water stays clear (for me).
Wayne