- Sku: 196
- Vendor: Seachem
Seachem Flourish Phosphorus
Seachem Flourish Phosphorus is a concentrated phosphate source for the planted aquarium. Phosphorus is one of the three key macro nutrients (nitrogen, phosphorus, potassium, or NPK) and often becomes the limiting factor to growth. Flourish Phosphorus is a safe potassium-phosphate solution that is nitrate free, so you can dose phosphorus to your plants' needs without raising nitrates. Browse our full range of additives and supplements and the rest of the Seachem lineup.
Why Seachem Flourish Phosphorus
How to Use
Shake well before use. Add 2.5 mL (half a capful) to every 125 liters (about 30 US gallons) twice a week, or dose as needed in response to signs of phosphorus deficiency. Adjust to keep phosphate in balance with your nitrogen. For best results, use as part of a complete fertilizer routine.
Choose Your Size
| Size | Best for |
|---|---|
| 100 mL | Nano and small planted tanks, or trying Flourish Phosphorus |
| 250 mL | Standard small to mid planted aquariums |
| 500 mL | Mid-size and well-planted tanks |
| 2 L | Large or multiple tanks, best value per mL |
Specifications
| Brand | Seachem |
|---|---|
| Type | Liquid phosphorus (P) supplement |
| Phosphate source | Potassium phosphate, nitrate free |
| Concentration | 4,500 mg/L phosphate |
| Dose | 2.5 mL per 125 L (30 gal) twice weekly |
| Sizes | 100 mL, 250 mL, 500 mL, 2 L |
Recommended Pairings
- Use with Flourish Nitrogen and Potassium for a full NPK routine, found in our Seachem range
- Browse all additives and supplements
- Shop everything for planted aquariums
Frequently Asked Questions
How do I know my plants need phosphorus?
Phosphorus deficiency often shows as stunted growth and darkening or browning of older leaves. Testing your phosphate level helps confirm it.
Why is nitrate-free important?
Many all-in-one products lock phosphorus and nitrogen in a fixed ratio. A nitrate-free phosphorus source lets you raise PO4 without also raising nitrate.
How does it differ from Nitrogen and Potassium?
Each targets one macro nutrient. Use Nitrogen, Phosphorus, and Potassium together to dose the full NPK your plants need.
Is it safe for fish and shrimp?
Yes, when dosed as directed it is safe for fish and invertebrates in the planted freshwater aquarium.
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Seachem Flourish Phosphorus
