What are your successful experiences in getting rid of blue green algae (cyanobacteria) in a freshwater tank?

they're growing all over my plants and driftwood and a little on the gl, gravel, overflow tubes, etc. Water chemistry is all good but nitrates are at 20-30ppm. I don't know the phosphate levels. I feed my fish 3x a day (maybe I overfeed a tad). Lights are on 8 hrs a day (low lighting)