I am going to take a wild guess here. Potassium Nitrate, N vs K is about 3 to 1. So raise 30 ppm of N you also raise 10 ppm of K. Macro consumes K, quite significantly. That's why you have K in fertilizers. Even assuming macro consumes no K, 10 ppm is very little compare to 450ppm of K for NSW. and 30 ppm of Nitrate is a lot and should last a while.
Wild guess it is Joe!
To find the percentages of K and N in KNO3, first add the molar masses:
K + N + (Ox3)
39 + 14 +(16 x 3) = 101
To determine percentages, divide this number into either N or P and multiply by 100 to get percentages:
Percent of Nitrogen = 14/101 x 100 = 13.9%
Percent of Potassium = 39/101 x 100 = 38.6%
So each molecule of potassium nitrate contains 13.9 % nitrate and 38.6 % potassium (by weight)....or more simply, for each molecule of potassium nitrate, you get one nitrogen and one potassium.....it's 1 for 1.