Awesome pic of the Vermetids. I have a page dedicated to them on the site for our old 75g tank - here: Vermetid Snails
I don't think that's what these are, though. Any chance of a closer pic? Are they just spots, or do they look "curly", or do they have 'legs' like spiders?
Some type of "spot" would be indicative of an egg. A "curly" shape might be a spirobid worm, which is a small feather duster. Here is a close up pic of these:
That is from this site: http://web.uvic.ca/~reimlab/Snails.html
Hydroids look like "spiders" (white spots with legs):
That picture (and more info.) is here: