Hi there,
I started using 3% saline about 2 years ago or something like that. I used it for a while and my new docs wanted to try me on 7% to see if I tolerated it. Well I coughed plenty fine with the 3% and 7% made me cough til I popped a rib out of place. Now I still have the 7% prescription but I dilute it to 5% instead of 7% - I use 10% and .9% to get the 7% - or 5%.
5% makes me cough plenty to do the job - just a bit more than the 3% but not so hard like the 7%.
Take Care,
Lindsey