Re: Ghosting... What actually causes it?
I noticed that when smoking Starbuzz and the likes (as in not Tangiers or Nakhla) the ghosting was really bad, and even worse with a Mya hookah. Myas have the rough brass on the inside, unless it's a bambino or one of the more expensive models.
Tangiers leaves minimal ghosting, and I even once read a post from Eric saying it cleaned the ghost flavors out of your hookah. It does a pretty good job of that in my opinion.
Nakhla also leaves very little ghosting, and that's one of the reasons I like smoking it so much.