This kit uses a liquid reagent to measure the acidity or alkalinity of freshwater aquarium water. Each kit includes a bottle of pH test solution, a glass test tube with cap, a color-coded reference chart, and printed instructions. To perform a test, a small water sample is placed in the tube, drops of reagent are added, and the resulting color is compared against the chart to determine the pH reading. Regular testing helps fish keepers catch shifts in water chemistry that can occur from fish waste, uneaten food, or the addition of tap water. The test tube should be rinsed promptly after each use to prevent reagent residue from staining the glass. No assembly is required, and the kit is intended for use as part of a routine aquarium maintenance schedule.