Interesting. Seems like a pretty straightforward test. I'll have to give that a try too just to put the nail in the coffin. Although I'd say it really already is completely identified thanks to you guys. Thanks againDino's can swim whereas other algae that might be similar-looking in bloom form cannot.
So if you swirl up a sample of mat to break it up, only dino's will re-coagulate into a mat or strands after a little while. (Being under light should help.)
There is a test that involves a paper towel, but I dunno if that's for diatoms or dino's.....not sure it's required.