I want to know how many ounces of fertilizer to mix per gallon of stock solution to be injected at a certain injector ratio to get a certain concentration of nitrogen.
I don't have mixing instructions from the fertilizer label, but I know the percentage of nitrogen in the fertilizer.

What is the desired nitrogen concentration? ppm N

What injector ratio will be used? 1 :

What is the nitrogen percentage of the fertilizer? %
(As a whole number. For example, for 20-20-20 input "20")>

Result: