Slime mold/algae does not show up on any of my grass. It grows on bare soil. This soil is never really wet and most of it is in almost full sun, so the typical growing conditions don't seem to fit what (specific) strain I have. I tried raking and then used a pressure washer to dislodge it, but it still hung around. Finally I resorted to a Fungicide, and that seems to be getting rid of it.