In areas with very hard water, which is used untreated in the washing machine , there is found scale deposits at the inner surface of these if appropriate measures are not taken. Detergents to avoid this scaling are added to many washing machines.
Merus maintains the calcium carbonate in the water under normal conditions so that, generally, far less scale or no scale at all is precipitated and deposited in these machines.  This results in savings in detergent of up to 50 % on washing machines and it is frequently possible to do without descaling additives entirely.
See as well a case in a Hotel laundry.