high quality upgrade: The total hardness test strips feature 5 levels and 4 parameters, improving test efficiency and accuracy. These strips provide reliable results, allowing you to check your water quality at home without the need to visit a store or rely on external testing, helping you save time and effort. Easy to distinguish: The water hardness test strips change color from green to purple for water hardness levels between 0–425 ppm (0–425 mg/L), with a clear and visible color contrast that makes it simple to compare against the included color chart. The test strips are made from environmentally friendly PLA material. Quick read, accurate result: Dip the strip in water for 2 seconds, hold it in the air for approximately 15 seconds, then compare the color to the chart on the bottle for immediate results—total testing time is only 17 seconds. Application: Water hardness requires periodic testing and monitoring. These strips can be used to test various water sources, including household faucets, well water, freshwater and saltwater pools, spas, hot tubs, drinking water, aquariums, and more. Features: 1. High-quality water hardness test strips are sensitive to environmental conditions and temperature changes. 2. If you have a water softener, quickly verify its performance by testing a water sample with these strips. 3. Helps maintain proper water hardness levels for aquatic life; different fish species thrive in varying hardness levels—soft, medium, or hard water. Regular testing supports healthy fish development. 4. Hard water can lead to mineral buildup in pipes and accelerate corrosion. Frequent testing helps ensure optimal water conditions in your plumbing system. 5. Prevent scale buildup on kitchenware and improve soap lathering efficiency by monitoring water hardness regularly. Specifications: Size: 4 x 4 x 11 cm (1.57 x 1.57 x 4.33 inches) Package weight: 54 g Quantity: 50 strips or 100 strips Note: 1. Please allow 0–1 cm error due to manual measurement. Ensure you are comfortable with this range before ordering. 2. Due to differences in monitor displays, the actual product color may vary slightly from images shown. Thank you. Package includes: 1 set of water quality test strips