Colors vary enough between tiers to be usable. Note that this is a wide range of peroxide levels, often more than typical spa use, but if you need to locate higher levels this will do! It would be nice to have more intermediate levels defined by the color on the bottle, but it can still be used.
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
TDS water quality tester - TDS water hardness meter (portable digital salt meter for water analysis)
9 Review
π PH 1-14 Extensive Storage Testing Monitoring: Optimize Your Storage with Precise pH Level Monitoring
6 Review
Accurate And Versatile Digital PH Meters For Food, Brewing, Hydroponics, Pools And More!
7 Review