Vermetid worms, probably. They're safe.
Your pictures aren't showing for some reason, but from what you described it sounds like they might be Vermetid snails.
is there a way to know for sure they are everywhere and what aboit that slime on the rocks the gray thing ?
This link might help. Make sure to click on the Photos icon though.
http://www.lionfishlair.com/hitchhikers-guide/vermetid/
Hmm. Maybe the Phyllohaetopterus sp. outlined in the link below? (Figure 10.)
http://reefkeeping.com/issues/2003-05/rs/
I'm not really sure about the slime, but those small brown stars your seeing might be Asterina stars. There's a lot of opinions out there regarding these things but I for one don't trust them at all. If one shows up I'll remove it ASAP.
Make sure to hit the Photos icon again.
http://www.lionfishlair.com/hitchhikers-guide/asterina/