Are these barnacles?

[My67rt]

I have what I think are small barnacles growing on the walls and rock work in my reef tank. Is this a good or bad thing? Can someone please confirm what they are

?
Attached are the best pics I could could get my phone to take.
Thanks!

 

[Reeffraff]

Hard to tell from the pics but they appear to be calcareous feather duster worms. This species stays small and can proliferate quickly. They are harmless and common in reef tanks.

 

[35ppt]

Spirorbid worms. Harmless filter feeders.

 

[Sisterlimonpot]

Spirorbid worms. Harmless filter feeders.

^^this^^