Recently I've been looking up info on teh water hardness settings on De’Longhi machines since it seems to be a topic that gets ignored in comparison to descaling. The machine actualy asks for you to measure your water and program in the hardness level. The official setting uses an Aquadur strip that comes with the machine, however any aquarium test strips (like API) will work the same. You dunk the strip for about a second, shake it off and look for how many red square there are. There will be somewhere between 1 and 4 red squares which will correspond to the hardness setting on the machine. The same measurements that the API and other aquarium water test strips measure are the same that De’Longhi machines use to determine water hardness. Both measure water hardness by measuring the amount of calcium in the water. So a reading of 3 on an API strip means the same as 3 red squares on a De’Longhi strip. Thus any deviation outside of that would be a matter of personal preference.
