Nano and RO models work on the basis of reverse osmotic membranes. (In the case of Nano, this is a nanomembrane — which passes about 30% of the incoming mineral composition.) So, in RO systems, water enters the pretreatment cartridge and is cleaned of mechanical impurities, color, odors, harmful substances and brought to a drinking state. Then this water is divided into two streams — one part goes into the reverse osmosis membrane and is cleaned almost to zero, after which it is stored in a tank, and the other part of the water is sent to the needle valve. You control this valve, regulate how much mineralized water gets to the desalinated one.
The Nano filter, although it does not give you the opportunity to change the mineralization, brings the water to values that will positively affect the digestion of coffee and will not leave scale.