Cardy Twin K+ Potassium Meter (C-131) - With extra solutionsProduct ReviewP Click on the link for more reviewsPMeasures Potassium (K+) in water, soil, plants food and other solutionsPEasily calibrate meter and measure samples. Measures in PPM.PMeasurement range of 39-3900 ppm. Easy measurement with only a few drops of sample.PAgriculture Solutions LLC includes additional wash bottle and 125ml each of additional calibration solution.