I am starting to hate my tank. The slope is collapsing, I have bad algae, my DSM pretty much failed,y shrimp are dying, my plants won't stay down, and I have surface film.
Try increasing the water changes and lower your photoperiod to 5-6 hours for a few weeks. That's how I turn things around. It's boring but it works. Then slowly ramp up the light once things are under control and you begin to have a larger plant mass.