Identify the equipment first
Open the exact model’s manual and look for the water-softener setup and salt-reservoir instructions. Do not assume that a cap near the filter has the same purpose on every appliance. Imported product descriptions are especially risky because US and European variants can differ.
A softener requires a hardness setting as well as the appropriate salt. Use the hardness of the water entering the machine, which may differ from the municipal supply when a household treatment system is installed.
Buy by compatibility
Choose dishwasher salt meeting the appliance manufacturer’s specification. Table salt, rock salt and other household products can contain unsuitable additives or have the wrong characteristics. The correct product is a maintenance supply, not a dishwashing detergent.
Compare the pack size with the available storage and ease of pouring. A funnel may help, but only use one compatible with the reservoir. Keep the cap area clean so it closes correctly.
Refill as the manual directs
The first fill can have different instructions from later refills, including whether water is added. Follow the sequence for your machine and remove spilled salt as directed. Do not leave loose salt on metal surfaces or improvise a treatment by sprinkling it over racks.
Salt does not replace rinse aid, and detergent packs do not necessarily eliminate the need to maintain a fitted softener. If the salt indicator behaves unexpectedly, check the manual rather than repeatedly adding more.