This is not an easy ID for sure I'm having to guess a start
Russ see if you think pics of chrysophytes online look like this it's hard for me to tell
One thing about its morphology though indicates UV to be a potential high value not a waste of time: no holdfast system, easily lifted off, and most likely has a water transition phase where intercept might be ideal
I didn't recall from your Dino thread if you are already using uv
It's not that it would remove it, it's that after full hand removal it's likely to help on regrowth arrest due to its characters...if you aren't using uv Amazon has a fine rental plan. Lasts about 29 days depending on seller. Judging by the neotherm heater I just got from them, it was someone else's rent lol it works so I kept it.