Maybe get a cheap microscope and take a look at it to confirm dinos or something else.
Ihad something very similar that was part of my new tank uglies. It was also stringy, gooey, but didn't have bubbles in it. I believe it ended up being a type of diatoms. My DI resin was really oldand "orange" color...i didn't change it since my TDS leaving my RODI system was raining zero. Once i changed the resin and filters...the stringy, mucus-like algae went away as i worked in the new water with my ATO and water changes! My LFS said it was diatoms...and that all diatoms don't look "dusty."