Phosdown

Phosdown is a fast acting phosphate remover alternative to lanthanum chloride which can cause undesirable issues. Its iron base is designed for safe and effective use in reef aquariums when used correctly. By targeting and binding free phosphate molecules in the water column, Phosdown helps reduce unwanted algae growth, stabilise nutrient levels, and promote optimal coral health and colouration.

 Key Benefits

• Reduces phosphate by 0.05 ppm per 1 mL per 100 L.
  
• Supports coral growth, coloration, and nutrient uptake.
  
• Helps prevent nuisance algae outbreaks.
  
• Leaves no residual iron or harmful by-products.
  
• Improves overall water clarity and stability.

How It Works
Phosdown uses an iron based solution that reacts quickly in saltwater. When added, the pH shift of the of the solution causes precipitation of phosphate molecules by binding them to iron. This creates insoluble compounds that are then removed through mechanical filtration (e.g., skimmers, filter socks, settling and removed on your next gravel clean). No residual free iron remains in your system.

Dosing Guidelines

• Standard Dose: 1 mL per 100 liters (26 gallons) Reduces phosphate by approximately 0.05 ppm.
  
• Start slow, begin with half the recommended dose for the first week. 
  
• Adjust gradually and monitor phosphate levels and coral response, then increase dosage. 
  
• Always increase the dosage slowly over a few days and test your water regularly to confirm your systems phosphate replenishment rate. 
  
• Maintain a balanced nitrate to phosphate ratio (~100:1 is ideal)

Example: If nitrate = 4ppm → phosphate should be ~0.04ppm. 

Application Tips

• Always dose into your sump or in a high-flow baffle section to ensure even distribution
  
• Avoid direct dosing into the display tank, instead use in your sump, baffle or dose slowly over the day to get safe and even distribution. Concentrated solution may irritate fish.
  
• Automatic dosing is ideal for controlled and consistent application. 
  
• Regular phosphate testing is essential to avoid overdosing or stripping nutrients too quickly. 

Safety & Handling

• Not for human consumption
  
• Keep out of reach of children
  
• Avoid contact with skin or eyes - eye protection and gloves recommended.
  
• If contact occurs, rinse thoroughly for 15 minutes and seek medical advice if irritation persists. 
  
• Acidic - handle with care

Best Used When

• Phosphate levels are creeping up or out of balance. 
  
• Algae growth is increasing despite good husbandry. 
  
• You want to fine-tune nutrient levels for coral colouration and growth. 
  
• As part of a regular nutrient management routine in a reef tank.