white circular things

[pace507]

I have noticed a ton of little white tubes that are circular in shape. Just wondering what they are. I suspect feather duster? but dont see anything sticking out of them. There are 100s of them and getting more and more. They are all bright white in color. I can't really take a picture since they are so small and all are about the same size.

What do you guys/gals think they are?

[OrionGirl]

Sounds like a stony tube worm. Not harmful, though they will leave those little white circular things on EVERYTHING. They tend to stay fairly small, and go in cycles. If you check about 1/2 hour after the lights go out, you should be able to see the feeding fan--probably bright orange. If you don't like them on the glass, scrape them off.