I do not think any RO service provider has any specific answers they just repeat 3-4 things they have picked up during day to day work
Eg:
1. Aquaguard has launched a new RO with something they call Green RO, they claim that water wastage is less and it is suitable for environment where raw TDS is approximate 500. I have been wondering how this works but I have found no answers except "Sir, isme Green
Membrane laga hua hai, wo kam TDS ke liye bana hai."
2. I have searched a lot but I could not find a filter with coconut shell based Activated Carbon all the shit available is Chinese Charcoal based carbon and it has a sponge base which I do not find hygenic specially at a stage after RO membrane. I have spoken to several people and they do not even know the difference.
3. I am still wondering if it is good to add a mineral enhancer cartridge as post filter but I could not find any good document that convince me to go one way or the other. I do not think any vendor can even tell me salts a single cartridge adds to the water.
I have so many questions and I do not think the so called professionals have convincing answers. I have given up now and have decided to go with what is easily available.