Seachem 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 utilised by the plants. Ammonium becomes available after conversion of urea (carbamide). Flourish Nitrogen also provides nitrate for those plants that can readily utilize nitrate as well.