Tetra EasyStrips 6-in-1 Aquarium Test StripsTetra EasyStrips 6-in-1 Aquarium Test Strips measure six important water quality levels - nitrate, nitrite, hardness, chlorine, alkalinity, and pH. The test strips are designed from the same technology used in medical and scientific laboratories, giving you fast and accurate results. Tetra EasyStrips are safe, non-toxic, and simple to use. Just dip directly into your aquarium, and read the results in seconds! It is recommended to check water daily with new aquariums and weekly for established aquariums.