Received my ReefCleaner's order last week. I noticed these white spots on, I think, the Nerite snails. Didn't think much about it at the time, but now one week later I have hundreds of them on the glass and back wall of me tank. They are about 2 mm wide and white in color. They are firmly stuck in place, but can be peeled off. They are flexible enough to bend in half without breaking. Doesn't look there's anything underneath them. Any ideas what they are?

That's a ballpoint pen for reference.

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