Cyanobacteria is a nutrient issue in the water column in low flow areas.
Increased flow will stop it from being able to grow, which higher flow is something sps
corals like, but it will not solve the nutrients in the water column.
Large water changes with ro
water on top of the weekly 10% water changes will get you ahead of the problem, though it takes time. Iíd also suggest that you donít use any of the liquid foods for coral, they polite your water column and are usually a big cause for this. Photosynthetic corals donít need fed as they get all they need from the lighting and broken up fish poop.