Test hardness before and after the unit. That separates a real treatment failure from old scale still dissolving off fixtures.
Check bypass and plumbing
A partially open bypass or unsoftened branch line can send hard water to fixtures even when the softener itself is operating.
Verify the hardness setting
Metered systems need the source-water hardness programmed correctly. An underestimated hardness value can cause the resin to exhaust before regeneration.
Salt-free is not true softening
Salt-free conditioners are designed to alter scale behavior but do not remove calcium and magnesium. Spotting and measurable hardness can remain.
Use a simple hardness test
A before/after hardness measurement is one of the fastest ways to verify whether the ion-exchange process is actually working.
Sizing and chemistry checks for Why Am I Still Getting Scale After Installing a Water Softener?
Water-softener decisions should be based on measured hardness, expected daily water use and peak service flow. “Grain capacity” is useful only when interpreted with the programmed salt dose and regeneration efficiency; the largest number on the product page is not automatically the most efficient operating point.
Iron changes the sizing problem. Some dissolved iron can be handled by ion exchange, but meaningful iron loading can foul resin and increase maintenance. When testing shows significant iron, manganese or sulfur, dedicated pretreatment is often more robust than asking the softener to solve every well-water problem.
Compare regeneration efficiency and long-term ownership
A well-sized unit should regenerate often enough to protect resin capacity without wasting salt and water. Compare usable capacity at the intended salt setting, estimated gallons between regenerations, service-flow rating and the amount of water used during regeneration. These operating details matter more over ten years than a small difference in purchase price.
Also consider valve support, replacement resin availability, bypass plumbing and local drain requirements. Salt-free conditioners belong in a separate category: they may reduce scale behavior in appropriate water but do not remove calcium and magnesium the way a true ion-exchange softener does.