How to increase tds in water purifier?

Important caution first: most people want to lower TDS (Total Dissolved Solids) for safety; intentionally increasing TDS is uncommon and generally not recommended unless you need to remineralize RO water slightly for taste and health. If remineralization is the goal: use a mineral cartridge or add a controlled amount of safe mineral salts (calcium, magnesium) or use a TDS controller/flow restrictor in RO systems to mix a small portion of untreated water back. Commercial remineralizer cartridges safely raise TDS and add beneficial minerals. Always follow manufacturer guidance and test with a TDS meter — aim for recommended drinking ranges (generally 50–150 ppm depending on guidelines).