Film or Blue-Green algae?

["Pete" <peteal at sympatico_ca>]

For the past year my 90gal had a constant growth of what I thought was film
algae (as described in the Aquaria FAQ) and so did a cleaning of the glass
every 3-4 days.

Went away on vacation and when I came back I found my filter had jammed.
Water chemistry was all over the place and the tank side were covered in
thick green.  This time when I cleaned them I noticed it was more like a
green paste that came off, not like a dust as before.

So now I was thinking maybe it was blue-green after all.  I did have the
same stuff on my plants (old leafs) but nothing like the quick growing stuff
people talk about.  So I cleaned it up and did a erythromycin treatment.
Now the glass has been crystal clear for two weeks.

So was it blue-green all this time but just slower growth than you usually
hear about or did the erythromycin treatment also kill the film algea?

PS. if you are cleaning your glass a couple of times a week, you might want
to take a closer look at the algea as it can be cured.

Thanks
Pete.