Features: Water Hardness Test Strips are very sensitive to the environment and changes to temperature. If you have a water softener installed, check its effectiveness quickly by taking a water sample and testing with the strips. The strip can help your fish grow well. Some fishes need it soft, some need it hard, and some very hard. Maintain the amount of hardness in the water by testing regularly. Hard water leaves mineral build up in pipes and hastens corrosion. Ensure that soft water runs in your system by testing often. Avoid hard water stains in your kitchenware by testing the water daily. Hard water also reduces the lather of soaps, making it less efficient. Specifications: Size: 4x4x11cm/1.57x1.57x4.33inch Package Weight: 54 g Quantity: 50 Strips/100 Strips Package Includes: 1 Set Water Qualtiy Test Strips note: 1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you place order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Please allow 1-2cm errors due to manual measurement.