If you are concerned about germs growing in your gallon of salt water, then make a new
batch every time you feel sinus infection coming on.
2. THE POWER OF SALT
Why does salt water work? Simply put, germs need water, and salt takes the water away from the germs.
There are two kinds of saline solution. Isotonic solution has the same concentration of salt as the human body. Hypertonic solution is saltier than the water in the human body.