Total dissolved solids (TDS) A TDS controller, like the name suggests is a device which helps control the TDS level of the water coming out of the RO Water Purifier.
TDS controller is a very simple device that is used to mix purified water with rawwater in an RO water purifier. This device ensures that the level of total Dissolved solids in your water is maintained. Based on the BIS bureau of Indian Standards the TDS in water should be In between 150 and 500.