Guides Grain Capacity and Salt Dose
Grain Capacity and Salt Dose Which Number to Size With
A softener's size name reflects a high salt setting. At the low setting that earns an efficiency rating, it removes less than half as much per regeneration, but gets about twice the grains from each pound of salt.
The Same Softener at Three Doses
| Softener | Low dose | Middle | Maximum | Sold as |
|---|---|---|---|---|
| Whirlpool WHES40 | 17,300 at 3.4 lb | 31,600 at 9.0 lb | 40,000 at 15.5 lb | 40,000 |
| GE GXSH45W | 19,904 at 3.89 lb | 48,801 at 14.65 lb | 55,424 at 25.42 lb | 45,000 |
| Morton M30 | 13,200 at 2.9 lb | 25,500 at 8.0 lb | 30,000 at 13.1 lb | 30,000 |
| US Water Matrixx | 15,000 at 3 lb | 24,000 at 6 lb | 32,000 at 15 lb | 35,000 |
Grains per regeneration, from each maker’s manual. The other four softeners we track don’t publish a dose table.
Grains per Pound Falls as Salt Rises
Low Dose
About 4,500 to 5,100 grains per lb on these four. This is where NSF's efficiency rating (at least 3,350) applies.
Middle Dose
About 3,200 to 4,000 grains per lb. Longer intervals, more salt per year.
Maximum Dose
About 2,100 to 2,600 grains per lb. The WHES40 and M30 size names are this figure.
What It Means in Salt
Three people, 75 gallons each, 15 gpg water: 3,375 grains a day. On the WHES40:
- 3.4 lb: regenerates about every 4.1 days, about 300 lb of salt a year.
- 9.0 lb: about every 8.4 days, about 390 lb.
- 15.5 lb: about every 10.9 days, about 520 lb.
Our math, from Whirlpool’s table, with one day’s use held back as reserve. Try your own numbers.
When There’s No Table
SpringWell, SoftPro, Aquasure and the Fleck 5600SXT kit give one capacity figure with no dose. For a rough guide, a generic resin data sheet puts 1 cu ft at 30,000 grains at 10 lb, 25,000 at 6 lb and 15,000 at 3 lb (Neo-Pure data sheet). That’s resin data, not a figure for any branded system.
Common questions
What salt setting should I use?
The lowest one that still gives a sensible interval between regenerations for your household. The calculator shows each option.
Why does my softener regenerate so often?
Usually because it’s set to a low dose for its size and your water use. That can still be the setting that uses the least salt.