Can you identify this algae and how to treat it?
It's really too hard to say without looking at it under a microscope. It may be a filamentous green, but that's only a guess. Filamentous algae usually respond to copper, particularly chelated copper (stays in solution and stays in contact with the algae). The good thing about chelated copper is that is doesn't affect larger rooted plants (except for Chara, which is also an algae). An alternative he could also try is diquat dibromide (like Reward or Weedtrine-D). That's good for filamentous algae but not planktonic algae. But, again, I'm not saying for sure that is a filamentous algae.
Hi Lois, thank you for your response. I took a couple photos of it under our microscope. Not the best quality but figured I would give it a shot.
The picture on the right side looks like a filamentous algae, but it's still pretty hard to tell. I'd need to see the cell itself. Also, there's a bunch of other material mixed in with it. Sorry I can't be more helpful.