API pH Test & Adjuster Kit can monitor pH from 6.0-7.6 in freshwater to help maintain healthy water conditions. All fish requires a specific pH level to thrive. pH in an aquarium can fluctuate due to fish waste, addition of tap water, and the build-up of natural acids. With API pH Test & Adjuster Kit, you can easily and accurately measure and adjust the pH level to maintain a healthy freshwater community aquarium. This kit includes: pH Up (1.25oz), pH Down (1.25oz), test solution, easy to read instructions on how to test and correct water conditions, color chart, and glass test tube with snap tight cap. 250 tests per kit.