Monitors pH to maintain healthy freshwater conditions. Taking a few minutes each week to maintain and monitor aquarium conditions is the key to a healthy aquarium. pH control is imperative to prevent the harmful effects of overly alkaline or acidic aquarium water on fish and plant life. Fish require a specific pH level to thrive. However, pH in an aquarium can fluctuate due to fish waste, addition of tap water and the build-up of natural acids. Use this kit to easily and accurately measure the pH level and maintain a healthy freshwater community aquarium. For use in freshwater aquariums.