It is quickly spreading all over tank
light grey in color
stringy, like hair or thread (but I though hair algae is green?)
has small balls on it (spores?), they are about the size of a period
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Your discription sounds like black brush algae or BBA I had it 2 months ago and
was advised by this forum to get some SAE's siamese algae eaters. I did and
have had no further increase in BBA These SAE's love eating the stuff but only
the new growth I don't know of anything that will eat the old stuff so I'm
afraid you'l have to get rid of it manualy good luck and
regards Art