Dull dishes after washing, cloudy glassware, scale build-up in the machine — most of these issues are caused by water hardness. Knowing your home's water hardness helps you choose the right amount of salt and suitable products.
What is water hardness?
Hardness refers to the amount of dissolved minerals (calcium, magnesium) in water. The harder the water, the more likely it is to cause scale build-up in the machine compartment, white spots on glassware, and reduce cleaning effectiveness. Most areas in Vietnam have moderately hard to hard water.
Hardness levels (°dH)
- 0–7 °dH: soft water
- 8–14 °dH: medium
- 15–21 °dH: hard
- above 21 °dH: very hard
From approximately 8 °dH upwards, water already significantly affects washing performance and machine durability.
How to measure at home
- Hardness test strip: quick and accurate — dip the strip in water, wait a few seconds, compare colors.
- Ask a technician to help measure when installing the machine.
- Consult your water supplier for the general level in your area.
Choosing products based on hardness
For medium to hard water, add Largo dishwasher salt and set the correct salt level on the machine. For very hard water, use Classic tablets or All-in-one combined with salt and rinse aid for clean, shiny dishes and a durable machine.
👉 See genuine German salt and economy combos at sieutietkiem.com.