Ina, you said, " I don't understand what the nebulizing 7% saline is but am trying to find it on the internet." I'm not the Internet but here's an Okie's take on why it tends to be favored among MAC sufferers. People who know about such things tell us that although lower concentrations of saline are helpful to the extent that they thin mucous which presumably facilitates coughing it up, However, when the concentration reaches 7% it not only thins, but also becomes lethal to mycobacterium avium complex (MAC) infections. Which is most likely the reason a few years ago after switching to 7% from a lower concentration of saline, my Pulmo (for the first time) following a chest X-ray, told me that the radiologist reported that the MAC infection had diminished in size compared to an earlier X-ray.