Yes it was cyanobacteria (help in identification)

[jfwilson54]

Thanks to the folks who posted about cyanobacteria. That's what I had, and indeed, the recommended treatment, Maracyn (erythromycin) worked.

Of course I was loath to hit my tank with antibiotics when I wasn't sure what kind of algae or non-algae I had. What really convinced me were the pictures of cyanobacteria at the following sites:
http://mikes-machine.mine.nu/algae_gallery.htm#Cyanobacterium_1
http://www.aquaticscape.com/articles/algae/bga1.jpg

Note: At two local LFS, they hadn't heard of cyanobacteria.

 

[Guest]

that's probably because they only know it by the name of Blue-Green algae. Or maybe they only new of it as algae and didn't know what kind it was. Sometimes at LFS you can find someone who really love's fish, especially if you find a good mom and pop store. But more often than not, its either a high school or college student just working part-time to make a few extra bucks.