White spores on glass?

[Titus07]

I discovered white spots on the inside glass of my tank this morning. I have not seen the tank in 24hrs and do not recall seeing these marks before....any ideas on what they might be? They are hard and about the size of a pin head.

 

[Kkubiak]

possibly the start of calcareous algea, diatoms, or sponges. Just a guess.

 

[MThompson]

they are probably mini tube worms. If you look really close you can see the fan sticking out of each one. I have about 1mil of these all over my display and sump. If you want to get rid of them, I use a metal tank scraper, they fall of really easy. I scrape them from the two sides and front of my display, everywhere else they just filter the water happily.