Aquarium test kits & water treatment Accurate - Interpet Tablet Test Kits are manufactured to pharmaceutical standards to ensure they contain the exact amount of reagent every time. Stable - Each test tablet is foil sealed for freshness. The tablets have a shelf life of over 2 years. Easy to use - Each kit comes complete with a safety plastic test tube with a tight fitting lid and a tablet crusher to aid mixing of the reagents. Informative - included in every kit is a comprehensive guide on how to use each test kit complete with important information on the results of the tests and how to remedy any problem in the aquarium.No.8 Hardness