Since there are thousands of species/types of algae, this is difficult. I had an entire text book called "The Algae of the Great Lake".
But anyway, when you pull it out, does it come out in slimy sheets?
Many true algae feel gritty to the touch, even though they look slimy.
I have a feeling it is cyanobacteria, not a true algae.
I would get it in only one or 2 tanks, out of maybe my total of 20 tanks.
It liked to cover pieces of wood, not only the substrate, and will sometimes blanket plants, so changing substrate would only be a temporaray fix, and may just come back.
For me, the only thing that worked, (I tried changing the light spectrum, more water changes, different filtration) was using a probiotic, pitting another bacteria against it, one that would out compete it.
I started adding Rid-X (yes the stuff you put in septic tanks) as a bio control, and watched it gradually melt away.
There is an entire sticky on its use in the disease section, it is also used to out compete pathogenic bacteria
The Use of Probiotics in Aquaculture
I also have a thread somewhere where I document my progress with photos
http://www.monsterfishkeepers.com/forums/threads/probiotic-experiment.544728/