The 551236 AquaChek Silver 100 count 7-Way Test Strips are the most comprehensive test strip product in our professional line providing results to 7 different tests in less than 1 minute. By using a test strip with so many results in one you save both time and money. For professionals this means you can service more pools with fast, easy accurate results every time. AquaChek recommends testing the water at each end of your pool at least twice a week for the cleanest and healthiest pool.