Tetratest pH Saltwater Kit (50 pack)The pH value of water is a measure of the degree of acidity or basicity, with values ranging from 1 (acidic) through 7 (neutral) to 14 (basic). The Tetratest pH Kit was professionally developed to accurately determine the pH level in your aquarium water. The kit contains one 10-ml test reagent (enough for 50 tests), a test vial, color scale, instructions, and recommendations. Test the water in your aquarium weekly to ensure optimum water quality.