Seachem Flourish dosing chart and calculator
Seachem's label doses scaled to your tank, plus what each dose adds in ppm. For any other volume, use the product calculator, which also mixes products into one plan.
Label directions
- Seachem Flourish: 5 mL per 250 L (60 US gal) once or twice a week. Seachem page
- Seachem Flourish Nitrogen: 2.5 mL per 160 L (40 US gal) twice a week. Seachem page
- Seachem Flourish Phosphorus: 2.5 mL per 80 L (20 US gal) once or twice a week. Seachem page
- Seachem Flourish Potassium: 5 mL per 125 L (30 US gal), 2–3 times a week. Seachem page
- Seachem Flourish Iron: 5 mL per 200 L (50 US gal), as needed to hold about 0.10 mg/L. Seachem page
Dose chart by tank size (mL per dose)
| Tank | Flourish | Flourish Nitrogen | Flourish Phosphorus | Flourish Potassium | Flourish Iron |
|---|---|---|---|---|---|
| 10 gal (38 L) | 0.8 mL | 0.6 mL | 1.2 mL | 1.5 mL | 0.9 mL |
| 20 gal (76 L) | 1.5 mL | 1.2 mL | 2.4 mL | 3 mL | 1.9 mL |
| 29 gal (110 L) | 2.2 mL | 1.7 mL | 3.4 mL | 4.4 mL | 2.7 mL |
| 40 gal (151 L) | 3 mL | 2.4 mL | 4.7 mL | 6.1 mL | 3.8 mL |
| 55 gal (208 L) | 4.2 mL | 3.3 mL | 6.5 mL | 8.3 mL | 5.2 mL |
| 75 gal (284 L) | 5.7 mL | 4.4 mL | 8.9 mL | 11 mL | 7.1 mL |
| 125 gal (473 L) | 9.5 mL | 7.4 mL | 15 mL | 19 mL | 12 mL |
What a dose adds (40 gallon example)
| Product | Dose | Adds (ppm) |
|---|---|---|
| Flourish | 3 mL | Fe 0.064, Mg 0.022, K 0.061, Cu 0 |
| Flourish Nitrogen | 2.4 mL | NO3 1.183, K 0.259 |
| Flourish Phosphorus | 4.7 mL | PO4 0.141, K 0.052 |
| Flourish Potassium | 6.1 mL | K 1.66 |
| Flourish Iron | 3.8 mL | Fe 0.25 |
Flourish (the comprehensive micro supplement) lists Fe 0.32 %, Mg 0.11 %, K₂O 0.37 % and Cu 0.0001 % by weight; we convert at 1.0 g/mL, an assumption. Flourish Nitrogen's ppm is Seachem's nitrate-equivalent: about half the nitrogen is from urea/ammonium, so a nitrate test reads lower. Flourish Phosphorus states 4,500 mg/L phosphate; Flourish Potassium 41,500 mg/L potassium; Flourish Iron 10,000 mg/L iron.
How to combine them
Seachem positions Flourish as the micro/trace base, with Nitrogen, Phosphorus and Potassium added "as needed". On alternate days from Flourish Trace if you use both. A heavily planted CO₂ tank usually needs far more N, P and K than the label doses add (compare 0.15 ppm PO₄ per Flourish Phosphorus dose with 1 ppm per EI dose), which is why many high-tech keepers switch to dry salts. A low-tech tank is often fine on Flourish alone plus root tabs; see low-tech dosing.