The number that makes settings comparable
Grains per pound of salt = usable capacity ÷ salt dose. It lets you compare two real operating settings even when the products have different nominal capacity labels.
Why nominal capacity can mislead
A softener marketed with a large grain number may not deliver that entire number at an efficient salt setting. Use the manufacturer’s capacity at the actual programmed salt dose whenever that data is available.
Annual salt is driven by your load
The calculator estimates regeneration frequency from usable capacity after your chosen reserve and your daily grain load, then converts the result into annual pounds, bags and cost.
Planning only. Actual valve programming, reserve logic, water efficiency and capacity depend on the exact system and manufacturer data.