Make sure you boil the water first, otherwise you risk getting brain eating parasites.
Not kidding.
Of course, Of course..

Also.. DO NOT use nasal rinse everyday..
Daily use will dilute your mucus so much, that it reduces the mucus's ability to fight off incoming germs and irritants..
mucus contains antigens to fight germs....
However, the system can become suboptimal in terms of piping over time, because pollutants in the air are far more numerous in modern day..
So.. once a week is good enough..