The Aquarium Lab Mini Test Kit from NT Labs is suitable for freshwater aquariums and performs checks on the 3 most important water parameters in an aquarium. The Aquarium Lab Mini Test Kit includes tests for pH, nitrite (NO2) and ammonia (NH3). The Kit comes complete with full instructions to help ensure you carry out the tests correctly, and to help restore perfect water quality should a parameter be incorrect. What is ammonia?Ammonia is excreted by the fish as a waste product. It is extremely toxic to fish, but is broken down into less toxic nitrite by the beneficial bacteria in the filter of your aquarium. Ammonia is most toxic to fish when the pH is alkaline and the temperature is high, so it is most dangerous in hard water aquariums. What is nitrite?Nitrite is produced by the beneficial bacteria in the aquarium and filters as they break down harmful waste ammonia excreted by fish. Although not as toxic as ammonia, nitrite is still very damaging to the health of the fish. Nitrite itself is in turn broken down into nitrate, which is much less harmful to fish. What is pH?pH is the measure of the acidity or alkalinity of the water in your aquarium. The pH scale runs from 1 to 14. Very acidic water is pH 1 and very alkaline water is pH 14. Neutral water that is neither acidic nor alkaline is pH 7.