
I love that they come with two test bottles. Sometimes it's faster than my pH pen and I mainly use it to make sure my meter's calibration is correct or when I just want to double check. It's just old school.

TDS water quality tester - TDS water hardness meter (portable digital salt meter for water analysis)
9 Review

Portable digital multimeter with sound continuity and thermocouple (electric tester) LTX DT-838
7 Review

Accurate And Versatile Digital PH Meters For Food, Brewing, Hydroponics, Pools And More!
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