Legend Potassium™

Potassium is one of several elements that are vitally important to maintaining a vigorous level of growth in a planted aquarium. Potassium can become depleted in a rapidly growing system or when the source water has a low mineral content. In these cases potassium could become the limiting factor to growth. Use Legend Potassium™ to prevent potassium depletion (signs of which include yellowing in older leaves) and maintain the highest level of growth.

In a strongly lit well-planted tank or in aquariums with few fish a lack of macronutrients may occur, which in turn can lead to poor plant growth. Legend Potassium™ brings the important macronutrient potassium into your tank. Your plants can draw on plentiful resources again and will thank you with lush growth.

The most easily obtained sources of potassium are potassium nitrate and potassium phosphate. Both of these sources add to either nitrogen or phosphorus as well as potassium, making it virtually impossible to target a specific NPK ratio. Legend Potassium ™is derived from potassium sulfate, allowing the user to adjust potassium levels without affecting nitrogen or phosphorus.

Weekly water changes of 25% to 50% are recommendable. The dosage can be raised or lowered depending on your requirements. If your tank water shows high readings of nitrate from the start, this fertilizer is not suitable for your aquarium, though. It has been designed to prevent the accumulation of large concentrations of macronutrients. If high levels of nitrate occur, please reduce the dosage. For maximum benefit, use with Legend Nitrogen™ and Legend Phosphat™.


Sizes: 100 mL, 250 mL, 500 mL, 1 L, 5 L


2 ml Legend Potassium™ per 100 liters of tank water adds the following nutrients:

K             1.00 mg/l


Dosage per 100 litres

Lots of light (>0.5 Watt per litre) + CO2  2 ml per day

Little light (<0.5 Watt per litre) + CO2     1 ml per day

No CO2 supply  2-4 ml per week


This dosage suggestion is just a guideline. The dosage may have to be raised or lowered depending on the conditions in your tank in order to give you good results.


  • Do not allow the potassium concentration to fall below 15 ppm
  • Do not contaminate the solution with aquarium water
  • Do not ingest and keep out of reach of children and pets
  • Store at room temperature. Protect from light, heat and frost
  • For aquarium use only


Legend Potassium MSDS 20230622.pdf


Shrimp Friendly

Storage: at room temperature. Protect from frost and heat. Keep out of reach of children and pets.

Use: For fertilization of ornamental plants in an aquarium only.
See the pack for detailed dosage recommendations. Note: Official guidance recommendations take precedence.

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Potassium fertilizer

Ideal for aquascaping and plant aquaristics

Compatible with fish and invertebrates

Aquatic plants finally can grow lushly again

Perfect for all levels of knowledge

Solution based on potassium (K)
no added nitrate or phosphate
Separate control of the nutrients