Spider-Web Algae

Ok, here's something I bet no one has heard yet.
Help, I've got an algae problem!
I've got this nasty filamentous algae and for the life of me I can't get
it to go away.  This is the stuff that grows in LONG spider web-like
strands and gets all tangled in just about everything.  I infested my
tank with the stuff somewhere along the way.  I can get in and twirl the
stuff up in a toothbrush but but no matter how hard I try to get it all,
it comes right back within only a few days.  It really likes making a
mess in my Cabomba. Luckily it's not terribly visible there.  However,
it is visible waving off the tips of just about every other plant.
This stuff is disgusting.  I read where this stuff tends to appear when
there is excess iron in the water.  Well my iron never excedes 0.2ppm
and is generally around 0.1ppm.  I even ceased Dupla24 drops for a few
weeks but the plant growth visibly suffered.  I also heard that this
type of algae doesn't do well in a high nitrate environment.  So I
tossed some Java Moss that was infested with it, into another aquarium
that tends to be neglected.  Nitrate levels in this tank have been as
high as 100ppm in the past but are usually around 60ppm.  The algae is
still kickin in that tank and I know there is zero iron in that
aquarium.  There isn't much light in that tank either but this stuff
just keeps on tickin'.
I've had this system up since Sept '95 and although the plants have
generally done very well, this algae really spoils the whole scene.
I've gone as far as re-adding a team of Mollys hoping they might munch
on it but so far they've shown no interest.  The SAEs, Ottos, etc want
nothing to do with it.
I've got automatic CO2, KH<=4, GH<=2, pH=6.8, substrate heating,
Temp=83, Dupla24, Dupla tabs, Duplagan, RO water cut with tap or mixed
with Kent products, 380 watts of VHO lighing on for 10hrs/day, no
measurable nitrates, etc.  The system has been very stable for over 4
As I said, most of the plants are doing great.  I have very little algae
of any other type.  A little spot algae on the glass, some stuff that
clumps in the gravel and around the base of rosette plants but nothing
unsightly or noticable except for this nasty spiderweb algae.
What's the cure?
Mike in sunny warm St. Louis