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. At API we understand the rewards and relaxation of fishkeeping because we have a passion for fish too!� For over 50 years API has developed premium solutions with proven and effective results for your family and ours.� API offers a range of testing kits, water conditioners, and nutritionally superior food, because we�re dedicated to making a better underwater world.