API pH Test Kit can monitor pH from 6.0-7.6 in freshwater to help maintain healthy water conditions. All fish require 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 Kit, you can easily and accurately measure the pH level and maintain a healthy freshwater community aquarium. This kit includes: a liquid dropper bottle, easy to read instructions on how to test and correct water conditions, color chart, and glass test tube. 250 tests per kit. Shipping weight: 1/4 lb.