The Nitrachek reflectometer is a pocket size digital measuring instrument for a simple and quick determination in the field of the nitrate content in water or in a watery extract of soil or crop. The method is based on read-out of nitrate test strips. After a test strip is held in the solution it is placed in the optical read-out apparatus. The instrument has a memory for up to 20 measuring sets with date/ time indication. The measuring range is 5 - 500 ppm (mg/l) nitrate. The reading accuracy is 1 mg/l. The instrument is supplied including case, test strips, calibration solution and accessories.