White circles on glass

Hi everybody,
I have some white circles forming on the back glass and powerheads of my tank. Does anybody have an idea of what this could be?
Some of the circles are almost the size if a quarter others are really small. I hope it's not bad stuff.

Thanks
Noble

 

If the white circles are the size of a pin head and are swirled, they are spirorbid worms. The larger ones your talking about are probably coralline growth as that is how the coralline growth starts!
That is all I can think of right now!

 

Thanks,
it all looks the same (no swirling) and it just started appearing out of nowhere. Hopefully it's just coralline.
Appreciate it, man your all over this place.

 

I would think thats a good sign I got some starting to pop up everywhere