Just dip an Aquachek Red strip in your spa (hot tub) or pool for one second and remove it immediately. You get test results in seconds. It couldn't be easier! To keep your spa at its best, test the water before each use. Test your pool at each end, at least twice a week. It's also a good idea to write down your results each time you test, so you can track changes over time. Comes with complete instructions in 15 languages: English, French, Spanish, Italian, Czech, Danish, Dutch, German, Greek, Hungarian, Polish, Portuguese, Russian, Swedish and Turkish.