What are these black things growing in my tank?

[Ponyboy_icw]

 

[ISpeakForTheSeas]

The first and last photos look like vermetid snails to me. I can’t see the middle pics very well, but I’m guessing they’re more vermetids.

Edit: you can see the curly tubes best in the last picture.

 

[Isaac Alves]

I agree with @ISpeakForTheSeas and also think they look like vermetids. I get these on the perimeter of my Vortechs and they’re dark purple to black in colorization.