Ok I would definitely recommend spreadingout that hairgrass as a background...At least behind the java fern. Be careful your java fern is not buried too deep... Only the stringy roots should be buried, the thicker rhizome needs to stay on top or the plant will die.
I know water movement is one way to beat cyano, that's why I asked about your filtration. What is your nitrate levels? I think high nitrates will encourage cyano. Weekly water changes & cutting back on feeding should help...