Flourish Nitrogen

  • Nitrogen supplement for the planted aquarium
  • 15,000 mg/L blend of nitrogen sources
  • Provides nitrogen in both the nitrate form and the ammonium form.


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 flourishing 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™. Flourish Nitrogen™ is safe for invertebrates such as shrimp.


BEGINNER: Use 2.5 mL (half a cap) for each 160 L (40 US 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.

Guaranteed Analysis

Total Nitrogen (N) 1%
Soluble Potash (K2O) 2%

Derived from: potassium nitrate, urea (iminium salt)


100 mL, 250 mL, 500 mL, 2 L, 4 L

To reach your desired level use:

caps or mL

Considerations: If using a “nitrate equivalent” value for Current and Desired Nitrogen levels, divide the result by 5.

A: Ammonium and ammonia are not the same thing. No free ammonia is released because the ammonium in Flourish Nitrogen is complexed and unavailable until utilized by the plants.

A: In studies we have done isolating the effects of the ammonium form and nitrate form of nitrogen on plant growth, we have found that most plants prefer to utilize nitrogen in the ammonia (ammonium NH4+) form. Note, however, that certain plants derive a greater benefit from the nitrate form (NO3sub>). That's why Flourish Nitrogen contains both the nitrate form as well as in an ammoniacal equivalent form.

A: This is true, but only when nitrogen levels become excessive, that is, when there is more nitrogen available than the plants can use. When this happens, it becomes available to algae. Nitrogen is still vital to plant growth, though. Flourish Nitrogen should be used in cases where there is a nitrogen deficiency

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0625 Flourish Nitrogen 100 mL
0626 Flourish Nitrogen 250 mL
0623 Flourish Nitrogen 500 mL
0628 Flourish Nitrogen 2 L
0629 Flourish Nitrogen 4 L