Seachem Flourish Phosphorus 250ml – Concentrated Phosphate Supplement for Aquarium Plants

Seachem Flourish Phosphorus is a concentrated phosphate supplement formulated to provide precise phosphorus dosing in freshwater planted aquariums. Containing 4,500 mg of phosphate per litre in the form of potassium phosphate, it allows aquarists to increase phosphorus levels without affecting nitrate concentrations.

Unlike combined nitrate and phosphate fertilizers, Flourish Phosphorus contains no nitrogen, making it ideal for correcting phosphorus deficiencies while maintaining complete control over nutrient balance. Regular supplementation promotes healthy plant growth, improves development, and helps prevent nutrient deficiency symptoms such as stunted growth and dark green foliage.

For a complete fertilisation programme, Seachem recommends using Flourish Phosphorus together with Flourish Nitrogen and Flourish Potassium.

Key Features

• Concentrated phosphate supplement
• Contains 4,500 mg/L of phosphate
• Provides phosphorus without increasing nitrate levels
• Supports healthy plant growth and development
• Helps prevent phosphorus deficiency
• Ideal for precise nutrient management
• Recommended for use with Flourish Nitrogen and Flourish Potassium
• Suitable for freshwater planted aquariums
• Bottle size: 250 ml

Dosage

Beginner dosing

• Add 2.5 ml (half a cap) per 80 litres of aquarium water once or twice per week, or as required.
• This dose increases:
  • Phosphorus (P): 0.05 mg/L
  • Phosphate (PO₄): 0.15 mg/L

Advanced dosing

The recommended phosphorus level is generally 0.15–1.0 mg/L, depending on plant density and aquarium conditions.

Seachem dosing formula:

• 0.2 × aquarium volume (L) × desired phosphorus increase = required ml of Flourish Phosphorus

Example:

• To increase phosphorus by 0.1 mg/L in an 80-litre aquarium:
  • 0.2 × 80 × 0.1 = 1.6 ml

Guaranteed Composition

• Total Phosphate (P₂O₅): 0.3%
• Soluble Potassium Oxide (K₂O): 0.2%

Technical Specifications

• Brand: Seachem
• Product: Flourish Phosphorus
• Volume: 250 ml
• Type: Phosphate supplement
• Main ingredient: Potassium phosphate
• Suitable for: Freshwater planted aquariums