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Seachem Flourish Phosphorus



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Flourish Phosphorus™ is a safe solution (4500 mg/L phosphate) of potassium phosphate that takes the guess work out of phosphate dosing. Unlike competing products that mix nitrate and phosphate in a fixed ratio, Flourish Phosphorus™ (being nitrate free) allows you to dose phosphorus according to the needs of your plants without the risk of overdosing nitrates. When used as directed Flourish Phosphorus™ will enhance and accelerate the growth of aquatic plants without enhancing algae growth. For maximum benefit use with Flourish Nitrogen™ and Flourish Potassium™.

Unlike competing products, Flourish Phosphorus™ is entirely nitrogen-free, making it possible to adjust the Phosphorus level in an aquarium without affecting nitrogen levels.


BEGINNER: Use 2.5 mL (half a cap) for each 80 L (20 gallons*) once or twice a week or as needed in response to signs of phosphorus deficiency (e.g. stunted growth, plant dark green).

EXPERT: The beginner dose raises phosphorus by 0.05 mg/L (0.15 mg/L phosphate). The ideal phosphate level will vary, but generally ranges from 0.15–1.0 mg/L. Use MultiTest: Phosphate™ to monitor phosphate levels. To target a specific phosphate increase, dose according to the following formula: 0.8vp=m, where v= volume of tank in gallons*, p=desired phosphate increase and m=volume of product to use in mL. For example to raise 20 gallons* to 0.1 mg/L phosphate you would use: 0.8*20*0.1=1.6 mL.