New to me algae....ID?

[saltyhog]

This stuff has appeared on my sand bed (along with a little bit of cyano) after a long battle with dinos. It's not extensive but is persistent despite manual removal. I've never seen anything quite like it microscopically. It's almost perfectly round and does not move at all. Anyone seen this or have any idea what it is?

 

[ScottB]

Possibly chrysophytes? Or golden algae. Can we get a pic of it on the sand under whites?
Does it
Look anything like the pics in my “symbiodinium treatment ideas” thread?