Nitrate test for aquarium. Biological filtration is a method that uses naturally occurring nitrifying bacteria to detoxify nitrogenous wastes. One type of bacteria (Nitrosomonas spp.) converts ammonia to nitrite while another naturally occurring bacteria (Nitrobacter spp.) converts the nitrite into a far less harmful form of nitrogen waste: nitrate. Nitrate is the final stage of the nitrify. Many invertebrates, unlike fish, are not tolerable to high nitrate concentrations. As a result, it is extremely important to make sure that nitrate levels do not reach high levels. In freshwater aquaria the optimal level of Nitrate should be below 20 mg/lt. Values of over 75 mg/lt should be avoided at all costs. In a marine aquarium the level should not exceed 20 mg/l. A level of 5-10 mg/lt is the maximum for reef aquariums. The NO3 reagent from ELOS, especially developed for fresh water and sea water aquariums, allows the determination of the Nitrate level with the help of a finely tuned colour scale which shows a range of 5 – 75 mg/Lt • Precise, thanks to the calibrated droplet • Simple to use • Equipped with a precision colour chart, measuring vial and syringe • Practical thanks to the easy-opening pack