Seachem Flourish Nitrogen – Concentrated NPK Nitrogen Source for Plants

Break the Nitrogen Bottleneck Holding Back Growth

In a thriving planted tank, nitrogen is often the first nutrient to run out, and once it does, growth stalls no matter how much light or CO2 you add. Signs like stunted growth and chlorosis mean your plants are running on empty.

Seachem Flourish Nitrogen is a concentrated (15,000 mg/L) blend of nitrogen sources, supplying both nitrate and the plant-preferred ammonium form. The ammonium is complexed and unavailable until plants use it, so no free ammonia is released into your tank. It gives plants that prefer nitrate a source too, works best alongside Flourish Phosphorus and Potassium, and is safe for invertebrates such as shrimp.

Flourish Nitrogen is formulated by Seachem Laboratories, the chemistry-driven aquatics company founded in 1979 in Madison, Georgia, where in-house chemists develop each product. It's the nitrogen component of the coordinated Flourish planted-tank system, one of the targeted macro (NPK) supplements that pair with the comprehensive Flourish supplement, Flourish Excel for carbon, and iron and trace dosing.

1. Beginner: use 2.5 mL (half a cap) per 160 L (40 US gallons) twice a week, or as needed for deficiency signs.
2. For smaller doses, note each cap thread is about 1 mL.
3. To target a specific increase, dose by the formula 0.25vn=m (v = gallons, n = desired nitrogen increase, m = mL of product).

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What It Does

A concentrated (15,000 mg/L) blend of nitrogen sources providing nitrogen in both the nitrate form and the plant-preferred ammonium form. The ammonium is complexed and unavailable until utilized by plants, so no free ammonia is released. Best used with Flourish Phosphorus and Flourish Potassium. Safe for invertebrates such as shrimp.

Directions

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, 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. To target a specific nitrogen increase, dose according to the 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), and m = volume of product to use in mL. For example, to raise 20 gallons by 0.20 mg/L nitrogen: 0.25*20*0.20 = 1 mL. Because one-half of the nitrogen is from nitrate, you can estimate nitrogen levels by doubling a nitrate reading.

Guaranteed Analysis

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

Ingredients

Derived from: potassium nitrate, urea (iminium salt)

Available Sizes

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

Why Seachem Flourish Nitrogen

• Nitrogen macro of the Flourish system: supplies the N in NPK so you can dose nitrogen precisely alongside Flourish Phosphorus and Potassium and the comprehensive Flourish supplement.
• Two bioavailable forms: provides both nitrate and the plant-preferred ammonium, with the ammonium complexed and unavailable until plants use it, so no free ammonia is released.
• Fixes nitrogen deficiency: breaks the bottleneck that shows up as stunted growth and chlorosis when nitrogen runs out first in a fast-growing tank.
• Concentrated and calculable: 15,000 mg/L, dosed at 2.5 mL per 160 L (40 US gallons) twice a week or by formula for a precise target.

Best For

Ideal for high-tech, high-light or heavily planted tanks that consume nitrogen quickly and show stunted growth or chlorosis, and useful in any low-nutrient system where nitrate stays low. Best for aquarists running a full NPK regimen who want to dial nitrogen in independently, and safe for shrimp and other invertebrates.

FAQ

Will this release ammonia into my tank? No. The ammonium is complexed and unavailable until utilized by plants, so no free ammonia is released, and half the nitrogen is supplied as nitrate.

How much should I dose? Beginners use 2.5 mL (half a cap) per 160 L (40 US gallons) twice a week or as needed for deficiency signs; to hit a specific target, dose by the formula 0.25vn=m.

How does this fit with the rest of the Flourish line? Flourish Nitrogen is the nitrogen macro in Seachem's coordinated planted-tank system, used best with Flourish Phosphorus and Potassium plus the comprehensive Flourish supplement, Flourish Excel for carbon, and iron and trace dosing.