Dishwasher (Granular) Salt
Your dishwasher has an integral water softening unit. If the water is soft (i.e. does not contain calcium particles), the detergent will work more effectively and there will be less streaking on dishes. Hard water can also block the washer jets with lime scale and cause deposits on heating elements, which will reduce the cleaning efficiency, increase electricity costs and shorten the life of the machine. All dishwasher manufacturers want you to get the best results from the machine - and soft water is one of the most important factors in achieving this. The way to ensure water remains soft is to regularly top up the reservoir with granular salt.
Three in one salt tablets do not activate the water softener. For optimum results, the reservoir should be topped up with granular salt. Three-in-one and 'salt action' tablets do not top up the reservoir and should be used in conjunction with granular salt for optimum results.
The salt that you use in your machine does NOT enter the wash chamber, so contrary to what some people may believe, it does not cause rust on cutlery. These deposits are usually from iron in the water and can usually be addressed by adding more detergent or lowering the temperature of the wash to 60 deg C. If you have other problems, view our Dishwasher Trouble Shooter.
The salt you add is used as part of a zeolite exchange process within the softener to remove limescale.
Using granular salt will mean that you won't need to use as much detergent and rinse-aid - saving you money!
How a water softener works
How much salt should I add?
Your machine may have a float indicator or a warning light to tell you when salt needs adding to the water softener. Often float indicators are difficult to see, and there is no accurate guide as to how much salt you need to add. Quite simply, just add granular salt to the reservoir until it won't take any more!
The softener will use the salt to replenish itself each time you wash. As an approximate guide, you should do a full top up about once a month. If your machine doesn't have a warning light, a good way to remember to check and / or top up is to do it on a regular day of the month (e.g. the first Saturday or the 15th).
Rust on cutlery is not caused by dishwasher salt (as it doesn't enter the wash chamber). It's corrosion or deposition by mixing metals in the dishwasher.
Can I use any salt?
No. Table, cooking, rock and sea salts may contain additives that can actually increase water hardness. Also, the fine consistency of some of these salts mean they are likely to clog when wet. Always use a high purity granular dishwasher salt because it is very pure and is the right consistency for use in your machine. Most of the dishwasher salt sold in the UK is from vast mines under the ground in Cheshire and is 'cleaned' to be of the highest purity.
Granular salt is the ONLY type of salt that should be used to regenerate the softener. Be aware that some varieties of ‘dishwasher salt’ use Dead Sea salt. This variety may contain minute insoluble organic matter that may adversely affect the resin within your softener over time. If you are in doubt about the origins of the salt, ask the retailer or manufacturer.