You should read/study about a method and apply it. Go to BarrReport.com for the Estimative Index theory. Maybe you try PPS Pro instead.
Regardless of the method, you will need to understand much more than just "this many grams of K2SO4 into my tank".
Some keywords for you to research: Macronutrients, Micronutrients, concentration, Estimative Index, etc.
Sent from my SM-G920F using Tapatalk