What does a pre-cyanobacteria bloom look like?

[discuspro]

I've just knoticed very fine fiber looking particles by the millions in my tank. They are not colored, yet, and are about 1/8 of an inch long each. They are not moving other than where the current takes them. I just did a five gallon water change yesterday with reef crystals and RO-DI in my 50 gallon system. What the heck!!

[GaryP]

I have never seen cyano form threads. Its usally more of a mat. That sounds more like entermorpha (hair algae). However, I'm sure there are many types of cyano and it could be one of these other ones.