White Spot ID

[CodeBlueMedic]

Hey folks,

I've been noticing these small white spots pop up on my glass, heater, filter, etc. They are hard like mini pebbles and take quite a bit of force to remove them. When you look super close, it looks like they have a tiny swirl, almost like bird poop. Any ideas what they could be?

Thanks so much

 

[cloak]

Spirorbid worms. (harmless)

 

[CodeBlueMedic]

Thanks!!!