Strange Algae/ Plant Problem

["Cory and Susanne Williamson" <cswilliamson at telus_net>]

I have recently been invaded by an algae/plant that is driving me nuts- I
will attempt a desciption of it, and please note that I have spent a fair
amount of time trying to sort out what this litte bugger is. As far as I can
tell it is not hair, staghorn or brush algae (all of which I have had or
seen pictures of). It is dark green (similar to java fern) coarse in texture
(almost like it has silica in its cell walls), very finely divided and
branching- it has a very similar disecting growth form similar to java moss.
It starts off as single strands attached to other plant matterial or gravel
and grows into dense matts the resemble old mans beard (a terrestrial
arboreal lichen) or green pot scrubbies. I have had great difficulty getting
rid of it- I have mostly tried to keep it in check using mechanical methods
which have thinned my once lush tank to lightly planted tanks that my wife
says needs more plants. My water chemistry is kept as per Tom Barr's advice
N ~5 ppm, P ~ 1 ppm, PMDD dosed about 30 ml at 35% once per week- H20
changes and 10 ml 3x per week. KH ~ 5 and pH 6.8. It grows reasonably fast
and will coat any organic or rough texture surface it can attach to. Small
strands break off and float around re-attached to other surfaces. Please
help with ID and other solutions i.e. herbivores etc.

Cheers,
Cory Williamson