EC-3185 3-in-1 EC/TDS/CF Soil Tester is suitable for all kinds of soil gardening plants, using high-quality probes, anti-rust and corrosion-resistant. Soil organic carbon levels that are too high or too low can stunt plant growth. Depending on the properties of the fertilizer and the different growth , different fertilizers will produce different soil conductivity. TDS values indicate exposure to total soluble solids in water. The lower the tds value, the lower the solubility of heavy metal ions in water. Nutrient solution is the key to cultivation, and different require different nutrient solution formulations. The EC-3185 does a good job of measuring and helping you with this. Name:EC-3185 Waterproof Soil EC/TDS/CF Tester Measuring range: Conductivity:0.00-4.00mS/cm CF:0.0-4.00CF Total dissolved solids:10-4000ppm Resolution: Conductivity:0.01mS/cm CF:0.01CF Total dissolved solids:10ppm Accuracy:EC:2% F.S. Automatic temperature compensation:0-50 Power supply:4*1.5V (AG13) (not included) Working temperature:0-50 Calibration:manual, by fine-tuning a little Colour:Green & White Material:plastic Size:170mm 35mm 35mm Package Contents: 1 * soil meter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.