JBL ProScape K Macroelements

JBL ProScape K Macroelements

  • Potassium fertiliser
  • Recommended level: 10 - 20 mg/l
  • The dosage can be checked with the JBL potassium test
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Healthy plant growth is based on the following three main pillars: A supply of light, a supply of CO2 and an adequate/optimal supply of mineral nutrients. The supply of nutrients is described by Liebig’s Law of the Minimum. According to this concept, the nutrient which is available in the minimum amount limits the growth of plants regardless of whether it is a microelement or a macroelement. Microelements are trace elements which plants need in small amounts, whereas macroelements are used for growth in larger amounts. In a well-planted aquarium, both microelements and macroelements are consumed in large amounts. Particularly when the fish population is small, the microelements, as well as the macroelements of nitrogen, phosphorous and potassium, quickly drop down to the minimum. The macroelements can easily be supplied by using JBL ProScape NPK Macroelements or by adding each of the individual components, nitrogen, phosphorous, potassium and magnesium, separately. If the latter procedure is selected, it is recommended to check the water values with the JBL Test Sets each time.

Potassium plays an essential role in all vital functions. In plants, for example, potassium is directly involved in stomatal regulation. In addition, potassium carries out important functions in the regulation of enzyme activities in the cells. Potassium is the third most important element of the macroelements taken up by plants. These are able to take up more potassium than they actually need and store it in the tissue. In nature, there are unlimited amounts of potassium available. In tanks which emphasise plants, though, potassium very quickly drops down to the minimum, so that it becomes a limiting factor for plant growth. The concentrations of potassium in the drinking waters usually used in aquariums vary considerably, depending on the water supplier. However, drinking water generally tends to have low potassium levels, so that it is usually far below the recommended 10-30 mg/l. It is advisable to determine the current potassium concentration of the water with the JBL K Test Set in order to find the right dosage of the JBL ProScape K Macroelements fertiliser. JBL ProScape K Macroelements supplies tank water with potassium in the form of water-soluble potassium salts.


  • For the fertilizing of plants in aquariums with few or no fish population, such as nano aquariums and aquascaping aquariums. Standard dosage in aquariums with CO2 fertilization and a lot of light: 5 ml/100 l.
  • Recommended level: 10 – 20 mg/l.
  • The dosage can be checked with the JBL potassium test.


Dosage per 100 Liter
Well lit tank (=1 Watt per liter) + CO2 6 ml per daily
Without CO2 4 ml per week

The normal dosage is 5 ml / 100 l of water for a very well-lit tank with >= 1 W / l of illumination and 2.5 ml/100 l of water for a tank that is not as well lit. The supply of carbon dioxide must also be considered. The following table shows recommended fertiliser concentrations according to the general conditions of the aquarium.

As actual precise consumption cannot be predicted, we recommend regularly checking the potassium level with the JBL K Test Set, especially prior to each follow-up dose.

2 ml JBL - ProScape K Macroelements in 100 l water yields a concentration of:
K 1 mg/l



JBL is a traditional German company with a very wide range of products for aquarists. From high-quality fish and shrimp food to external filters and water plant fertiliser, JBL offers a wide selection for aquarium enthusiasts.

JBL's research and development constantly brings new, innovative products onto the market. Whether aquascape, fish aquarium, shrimp tank with a scurry factor or a pure water plant aquarium in Holland style, JBL offers suitable aids for set-up and maintenance for all these directions.

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