TDS Meter V1.0 Development Board Water Meter Filter Measuring Water Quality Measurement Module TDS Meter Board for ArduinoFeatures:This is an forArduino-compatible TDS sensor/Meter Kit for measuring TDS value of the water, to reflect the cleanliness of the water. It can be applied to domestic water, hydroponic and other fields of water quality testing. You may also check Liquid Sensor Selection Guide to get better familar with our liquid sensor series.TDS (Total Dissolved Solids) indicates that how many milligrams of soluble solids dissolved in one liter of water. In general, the higher the TDS value, the more soluble solids dissolved in water, and the less clean the water is. Therefore, the TDS value can be used as one of the references for reflecting the cleanliness of water.