Aquarium Systems Test Kit A new range of test kits from Aquarium Systems that accurately test your pond/aquarium water. Water quality is an important part of pond and aquarium keeping. One of the most crucial things to test in order to maintain optimum water quality is the pH levels. pH levels indicate the ratio of alkalis and acids in the water, and changes in these levels are common. Fish are very sensitive to pH and so regular monitoring is necessary. Range 4-10 Keep out of reach of children. Contents: 2x10ml test reagent Measuring cylinder Colour chart Instructions