Several companies make pre-made additives. I have found that commercially available table salt is effective and less expensive. Some patients, however, prefer the pre-mixed solutions.
The nose is best washed with diluted salt water. No salt or too much salt will cause irritation or a burning sensation. Most people use 1or 2 level teaspoons of common table salt in 500 milliliters (1 pint) of water. Distilled or cooled, boiled water is sterile and is excellent for nasal irrigation. The water temperature is controversial. Some like cold water and some like it hot. 98.6 Fahrenheit, (37 centigrade) is the body temperature ideal for nasal irrigation. The coolest water that should be irrigated through the nose is 72 Fahrenheit and the warmest 102 Fahrenheit. Ten percent of patients say the standard salt solution causes burning. For these individuals, one quarter to one half teaspoon of baking soda changes the acidity (pH) and will ameliorate the burning problems. A slightly acidic solution is preferred so baking soda should only be used if necessary for comfort.
Fill your nasal irrigator with the chosen water temperature and salt concentration. Lean over the sink. Place the irrigator up to your nose. Let the water run into your nose. It will run out the opposite side or out your mouth. Tilt and twist the irrigator side to side and up and down directing the water flow into all portions of the nasal cavity. When the first nostril feels clean, switch to the opposite side.