Great link. Thanks.Definitely not Riccia.
Check out this link and scroll down to Staghorn Algae and then Hair Algae:
http://www.aquariumalgae.blogspot.com/
Good luck.Staghorn algae:
Looks like individual strands of hair algae but tends to grow in single branching strands like a deer antler and is grey-green. Seems to grow mostly on tank equipment near the surface. Difficult to remove mechanically. Soak affected equipment in a 25% solution of household bleach and water to remove it.