I don't think this algae is any sort of problem. It is a short fuzzy or
smoth-ish covering. Maybe 1/4 inch. In the late summer, small patches
of it rise up...air, I am guessing.

Jim

Phyllis and Jim Hurley wrote:
Our cement pond runs a steady coat of dark black/bule algae that nicely
hides all colors. People have named it from time to time. Can anyone
help us out?

Thanks

Jim