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Softener Sizing Calculator Regenerations and Salt per Year
Your hardness and household in, then days between regenerations and salt per year for each softener at every published dose.
Don’t know your hardness? Start with the Hardness Check.
Your Water and Household
Compensated hardness15gpg
Grains removed per day3,375grains
Capacity for your target27,000grains per regeneration
Every Softener at Every Published Dose
Highlighted: the lowest salt setting that reaches your target.
Turn on JavaScript to use the calculator. Every capacity table is on the system pages.
How the math works
- Hardness: mg/L ÷ 17.1 = gpg. Each ppm of clear-water iron adds 4 gpg (Hydrotech Iron Guard manual).
- Daily grains: people × gallons per person × compensated hardness. 75 gallons per person is the figure in the Aquasure Harmony manual and the Hydrotech manual.
- Days between regenerations: capacity at the dose ÷ daily grains, minus one day held back as reserve (the same people × 75 gallons reserve both manuals use).
- Salt per year: 365 ÷ days × pounds per regeneration. Bags assume 40 lb.
- We use only the doses each maker publishes and never fill in between them. Systems without a dose table show their nameplate capacity and no salt figure.
Using the Results
- Size on the dose you’ll run. A softener sold as 40,000 grains may deliver 17,300 at its efficient setting. The table shows each one.
- Lower doses save salt. Grains per pound fall as the dose rises, so the low setting wins on salt per year. The extra regenerations can use more water.
- Don’t know your hardness? City water reports list it. On a well, a lab test also gives iron, which softeners treat as extra hardness.
- Real use varies. Demand valves adjust to your actual water use, so treat these as planning figures.
More: grain capacity and salt dose · sizing guide · all systems