Need Help with Algae problem

A few months ago I posted on the ability to grow tanks near windows.  In 
the past I've had pretty good luck as long as direct sunlight hit the 
tank less than 3-4 hours per day and it was shaded in summer.  I have a 
55 gal tank I set up in July that was getting 5-6 hours per day of direct 
sunlight.  Due to an 'overstock' of juvenile angelfish I had to raise 
about 50 in the 55 gal. planted tank.  I think the combination of direct 
sun and angels with voracious appetites has caused my current algae problems.

My question is: what kind of algae do I have, and what do you think of my 
current treatment?

The algae is filamentous, about 1.0 to 2.0 cm long.  The threads grow 
mostly on the plants, and also on the front pane of glass.  They do not 
occur in bunches, but seem to cover the plant surface uniformly.  The 
density is somewhat less than what I think is called 'fur' algae.  
Lately, it has been collecting small 'particles' that are circulating in the 
tank, and the threads look grey and rather disgusting.

I've started covering the front of the tank, and have reduced the 
photoperiod to 7 hours.  Also do 40-50% water changes every 2 weeks.  
Have removed all but 10 of the angels,and reduced feeding.  I'm going to 
do a 50-60% water change tonight and turn the lights out and cover the 
tank for two days.  Any other ideas?

 I have about 
4 oto's in the tank; what other algae eating fish would be helpful? Would 
SAE's be helpful?  What effect will feeding the other fish in the tank 
(flakes, frozen blodworms and brine shrimp) have on the SAE's desire to 
eat algae?  Are Ancistrus a better choice?  

Thanks in advance for any comments,

Paul Bucciaglia

tank stats:

55 gal.
4 40W lights: 1 ultralume, 2 GE Chroma 50, 1 syl. daylight
yeast CO2 into aquaclear 200 PF
powerhead for circulation
>80 gravel surface planted
micronutrients 3X per week
fish load: 10 half dollar size angels, 6 Papilochromis altispinosa, 5 
corys, 4 otos, 6 von rio tetras.  

I have a 30 gal with similar set up and fishload that is algae free.