Review on Bluelab BLU8000 Grower's Toolbox Pen with Conductivity Tester and Probe Care Kit - Easy Calibration TDS and pH Meter for Hydroponic System and Indoor Plant Grow – Durable Plastic Construction by Steven Lane

The product is beautifully packaged. There are no problems with the EU sensor. The pH controller is a different story. It worked for 2 months and then broke down. The pH is initially high and then steadily decreases until it reaches 2.2-2.1 and stays at that level even in the 7.0 calibration fluid. When I try to calibrate the meter, there are repeated calibration errors in both the 7.0 and 4.0 ranges. The meter was cleaned and moistened every 28 days, the probe did not dry out, 3 drops of Kci storage solution were added every week. After rehydrating 2 more times the meter started to respond a little, managed to calibrate it to the 7.0 scale but it still doesn't work on the 4.0 scale so I won't get a proper reading give. Complete disappointment after only a few months of proper maintenance and care. I will not buy the product in blue again.