You might want to start with the 3% and see how you tolerate it. 7% can be a little more harsh.

My pulmonologist put me on 3% saline after diagnosis. After 3 years nebulizing and reading on this site that 7% was better I switched. I found that 7% works far better in the AM but if I use 7% in the evening coughing interfered with my sleep. So now I use 7% in the morning and 3% around 5 PM. When I shared this with my pulmonologist he didn’t know about 7% but said he had no problem ordering it. Medicare and most insurance companies do not cover saline as there is no meds in it.

I found 7% definitely more effective in the morning but found 3% better later in the day - generally around 5PM. I had nebulized with 3% for 3 years until I read about 7% on this site. I’m bringing up more green mucous with 7% almost immediately after nebulizing.