Work out water softener resin volume instantly with clear inputs, formula shown and shareable results.
Resin volume is the hardness load between regenerations divided by the resin's operating exchange capacity, typically 40-55 kg of calcium carbonate equivalent per cubic metre at practical salt dosages. Regeneration salt is around 100-200 kg per cubic metre of resin, and higher salt dosing buys higher capacity at lower efficiency.
Hardness load
Load (kg/day) = flow (m3) x hardness (mg/L) / 1000
Resin volume
Resin (m3) = load per cycle / operating capacity
Softener regeneration brine is high in chloride and may be prohibited from discharge to sewer or watercourse. Confirm local rules before installation.
Regeneration is an equilibrium process. More salt drives more calcium off the resin, raising capacity, but with diminishing returns — doubling salt might add only 30% capacity, so there is an economic optimum.
Yes. Spent regenerant is high in sodium and chloride, which most treatment plants cannot remove and which harms watercourses and irrigation. Some jurisdictions restrict or ban discharge.