Nitrogen is one of the main three macro nutrients (nitrogen, phosphorus, potassium: NPK) required by plants and can often become the limiting factor to growth in a nourishing system. Flourish Nitrogen is a concentrated (15,000 mg/L) blend of nitrogen sources. It provides nitrogen in both the nitrate form and the plant-preferred ammonium form. However, no free ammonia is released because the ammonium in Flourish Nitrogen is complexed and unavailable until utilized by the plants. Flourish Nitrogen also provides nitrate for those plants that can readily utilize nitrate as well. For maximum benefit use with Flourish Phosphorus and Flourish Potassium.DIRECTIONS: BEGINNER: Use 2.5 mL (half a cap) for each 160 L (40 gallons*) twice a week or as needed in response to signs of nitrogen deficiency (e.g. stunted growth, chlorosis). For smaller doses, please note that each cap thread is approximately 1 mL. EXPERT: The beginner dose raises nitrogen by the same degree that 1 mg/L nitrate would. This dose is sufficient to provide approximately 4 g of growth (dry) or about 20 g (hydrated) over a 1 month period (assuming all other necessary nutrients are provided). For increased growth use proportionately more. To target a specific nitrogen increase, dose according to the following formula: 0.25vn=m, where v= volume of tank in gallons*, n=desired nitrogen increase (if using a ?nitrate equivalent? value for ?n? then use a factor of 0.05 instead of 0.25 in the formula) and m=volume of product to use in mL. For example to raise 20 gallons* by 0.20 mg/L nitrogen you would use: 0.25*20*0.20=1 mL.Because one-half of the nitrogen in Flourish Nitrogen is from nitrate you can get a reasonable estimate of nitrogen levels by doubling a nitrate reading, or, you can use Seachem?s MultiTest: Total Nitrogen (coming soon!) to accurately measure total nitrogen while distinguishing between nitrate, ammonia and organic nitrogen.