It appears like you have some green cyanobacteria. Your best defense is to scrub each rock with a toothbrush and siphon your substrate. Then start an aggressive water change routine to get the nutrients under control as well as removing the foam filter. There is not much in the line of herbivores that will eat that stuff so manual removal is your best bet plus nutrient reduction. Are you using RO/DI water? And add more flow!
