Staghorn or Red Algae? and Treatment

     I currently have an algae growing on some Giant Sag and Corkscrew Val.
 From all the FAQs that I have read, I believe that it is either Staghorn or
Red Algae.  It is about 3mm long and appears to be gary, hard and branching.
 When I try to remove it, it just breaks off in the middle and grows back.
 Can anyone either confirm or refute the algae type, and offer a treament for

     - Keith