Use the API? pH Test Strips as a quick and accurate way to test pH levels in your water. These test strips measure a wide range of pH, from 6.0 to 9.0 ppm, to help you keep aquarium conditions safe for your fish. Product comes with desiccant-lined tube with snap-tight cap, highly precise color chart for accurate water parameter readings, and information on how to correct unsafe water conditions. For use in fresh and saltwater aquariums.