1. Your water
2. Your usage
Recommendation
—
grain softener (rated capacity)
Compensated hardnessDaily water use
Grains removed per dayRequired usable capacity
Resin volumeTypical tank
Gallons between regensActual regen interval
Salt per year (est.)40-lb bags per year
Standard sizes
| Rated | Resin | Tank | Usable (eff.) |
|---|
How it works
- Compensated hardness = hardness (gpg) + 4 × iron ppm + 2 × manganese ppm. ppm÷17.1 = gpg. (Nelsen, WQA)
- Capacity = compensated hardness × gallons/day × days between regens. Aim for ~1 regen/week; oversizing wastes resin life and salt.
- Efficient salting gets ~3,300 grains per lb of salt but only ~75% of rated capacity, so we size the rated number up to cover it.
- Most residential softeners only handle ~2 ppm ferrous iron; above that, add an iron filter first.
Don't guess your hardness
City water: check your utility's Consumer Confidence Report. Well water: test it. A titration kit beats strips.
- Hach 5B hardness test kit
- Hardness test strips (quick check)
- Shop softeners in your size
- Softener salt pellets
- Iron filters (iron over 2 ppm)
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