I have had sinus infections and sinus headaches for years.
I had tried the salt and water irrigation. I found that it burnt my nose. I did some experimenting and came up with the following. It has done wonders for my sinus's.
One teaspoon of baking soda (which is close to our body make up) and one teaspoon of either sea salt OR coarse pickling salt, with one cup of distilled water. Tap water is too hard on the membranes of the nose. Irrigate the nose twice a day.
After doing this for only a few days I have never had another sinus infection or sinus headache.