Knowing a little too much about something is usually a smaller error than not knowing enough.
Special Thanks to:
Gentle Readers everywhere.
Conversion for US Gentle Readers
It is often easiest to make calculations in milliliter (ml) or grams (g) per liter. Unfortunately is it also often easiest to actually mix nutrients by the gallon.
If you have the application rate in liters, and you want to calculate how much to add for a gallon, select the first option. If you have the application rate in gallons, and you want to know how much to add per liter select the second option.