White specks - under microscope

[Kobooi]

Since yesterday I have tiny white specks everywhere on the glass and the cables of the gyres. I thought spirorbid worms as I have those on the glass in the sump. Once they come out of the water, they are brown immediately, not white. So I've put one under the microscope and it look likes something else. It has black little brushes (see second picture in the middle).
Images are not great (the specs are hard like sand, so I can't get a flat image completely in focus, and ignore the circle around it which is the edge of the water drop) - but does anyone know what these are? Thanks.

 

[Ron Reefman]

bump

Does anybody even have any guess as to what these are?

 

[alliw]

Bump

Anyone? What does calcium Carbonate look like under a microscope? I have these tiny white hardened specks on my glass and lots of equipment and also on rocks. I have a TON of feather duster tiny worms in my tank. I feel like they can strangle corals. I have a Goni and a galexia that look like they’re being tortured by these feeders although many folk say they’re harmless. So should they grow into corals?