Clear Eggs On Glass?

[Marcosreef]

I have these clear egg like sacks all over the glass and especially in the corners of the tank. They seem clear, about 1mm in size, and filled with what seems like grains of super fine white sand. Any ideas on what this might be? Whatever this is seems to multiply overnight.
Sorry no pictures yet...

 

[Reefer2b]

Snail eggs. I added a bunch of trochus, cerith and nassarius snails to my tank and saw the same thing right away. After a while, you'll see a small hole has been cut out of the egg sack and all the little "white grains of sand" are gone. If any survive, a couple months later, you'll see some tiny new snails populating your tank.