The scale is only blue and turning the screw doesn't seem to change anything. Also, the instructions are for a different gauge than the one I bought. Zero advantage for me.
TDS water quality tester - TDS water hardness meter (portable digital salt meter for water analysis)
9 Review
Accurate And Versatile Digital PH Meters For Food, Brewing, Hydroponics, Pools And More!
7 Review
80 Pieces Water Test Litmus Strips Litmus ph Paper Soil Acidity Meter Liquid pH Tester 1-14
10 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