Keep your fish healthy and thriving by testing your aquarium water regularly with easy-to-use API 5-in-1 TEST STRIPS. API 5-in-1 TEST STRIPS for freshwater and saltwater aquarium help fish owners measure levels of Nitrite, Nitrate, Carbonate & General Hardness, and pH found in aquarium water. In order for fish to thrive, water must be similar to that which could be found in their natural environment. Poor water quality can cause fish stress, illness and even death. Just dip a strip directly into your aquarium and use the color-coded chart to determine if your water is safe, or if adjustments are needed. Then follow the recommendations to treat the water - it's that simple. With API Aquarium products, it's easy to keep a beautiful saltwater, freshwater or reef aquarium. For over 50 years, API has been creating innovative, research-driven solutions that make it easier to care for your fish and aquarium. API Aquarium Treatment Supplies are designed to work in conjunction with each other to provide best results to control algae, promote healthy bacterial growth and help control and cure fish diseases and conditions such as ich and fin rot. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. With API, you can spend more time admiring your fish, and less time scrubbing your tank. Make sure to use all products as directed in order to ensure the best results.