Pond weed type?

[audi321]

Hi all, Does anyone know what type of pond weed this is in my mums pond?

Looks like fluffy candy floss, tried blanket weed killer and it doesn't touch it. It's mainly attached to the bottom liner (rather than floating on top)

Thanks in advance

[audi321]

Cheers guys. Yes it does cover the ugly black plastic liner so isn't too bad.

The water is crystal clear which I guess makes it look worse than it would if it wasn't.

Might just leave it then. There's a pump and uv light so maybe that needs changing.

Thanks again.