a generic ro would do for 600tds. as per indian standards, 500tds is the upper limit for potable water. https://www.amazon.in/Copper-RO-Purifier-Automatic-Controller/dp/B0BJ6P3LSK or https://www.amazon.in/Kinsco-Adjuster-Purifier-Dispenser-Machine/dp/B09GLW2F7L under 5k, gets the job done. can...