Calibration is lost over time. Keep clean when you use it regularly. I use between multiple tanks. But it's only been a month, and I found it drifted off a bit.
Portable digital multimeter with sound continuity and thermocouple (electric tester) LTX DT-838
7 Review
Digital PH Meter Tester - Tiaoyeer Water Quality Tester With ATC, 0.01PH High Accuracy, 0.00-14.00 Measurement Range, 0.01 Resolution For Drinking Water, Aquarium, Swimming Pools, Hydroponic
8 Review
80 Pieces Water Test Litmus Strips Litmus ph Paper Soil Acidity Meter Liquid pH Tester 1-14
10 Review
TDS water quality tester - TDS water hardness meter (portable digital salt meter for water analysis)
9 Review
π Enhanced Precision with Backlit Professional Manometer for Differential Ventilation
6 Review
Portable Handheld Manometer π for Accurate Pressure Differential Measurement
5 Review
π‘οΈ Continuous Temperature Monitoring with Relative Humidity Integration
4 Review
π Dioxide Controller for Digital Gas Monitoring
5 Review