I currently have a sinus infection from a cold I caught last week. I'm taking antibiotics for it but am intrigued with this sinus irrigation that some have talked about. My questions are - why does the water have to be distilled? Can't I just boil tap water to sterilize? And I see some use kosher salt, some use sea salt, and some use regular table salt. Does it matter which? And I understand how the irrigation gets to some of the sinuses when your head is tipped, but how can it get to the ones in your forehead? Is that a silly question? I mean, if the water is going from one side of my nose to the other, I know it's probably reaching some of the sinus cavities close to that area, but how does it reach the ones in your forehead and behind your eyes?