Easy-Life Kalium potassium fertiliser for aquarium plants
Regular price
5,90 €
Regular price
Sale price
5,90 €
Unit price
/
per
| Contenance | Price | Price per L | vs 250 ml |
|---|---|---|---|
| 250 ml | 5,90 € | 23,60 € | — |
| 500 ml | 9,50 € | 19,00 € | −19 % |
Kalium is an Easy Life liquid fertiliser that supplies potassium to aquarium plants. It is a concentrated fertiliser: 10 ml per 100 litres raises potassium by 4 mg/L.
It is dosed at 10 ml per 100 litres per week, in bottles of 250 or 500 ml.
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The summary
- Which bottle: 250 ml treats 2,500 L, 500 ml treats 5,000.
- What it provides: concentrated potassium, with no added nitrogen or phosphorus.
- How to dose it: 10 ml per 100 L each week, depending on the test.
- How to know: a K test shows whether you need to add any.
Concentrated potassium for planted tanks, where it is most often lacking
Easy-Life Kalium is a liquid potassium fertiliser for planted aquariums, with no added nitrogen or phosphorus. Concentrated, it raises potassium by 4 mg/L for 10 ml in 100 litres, a dose to be repeated weekly according to the result of a K test. The 250 ml bottle treats 2,500 litres, and the 500 ml bottle treats 5,000.
Potassium is one of the three major plant nutrients. It regulates water exchange in the cells and plays a part in photosynthesis as well as in the strength of the tissues. Aquarium plants consume a lot of it, especially in a brightly lit tank where they grow quickly, whereas fish excrete little of it and tap water often contains little, particularly where it is soft. Potassium shortage is thus one of the most common deficiencies in planted tanks, and Kalium lets you correct it on its own.
🌿 Spotting a deficiency
A potassium deficiency shows first on the oldest leaves: small holes appear, the edges turn brown or necrotic, and the leaf blade yellows while growth slows. This yellowing resembles that of an iron deficiency, which tends to affect the young leaves. A potassium test lets you tell the two apart before correcting, and avoids adding an element that is not lacking.
Brightly lit tank
Plants grow quickly and use more potassium.
Freshwater
Water with low mineral content contains little of it.
Fast-growing plants
Fast-growing stem plants use it up first.
Old leaves with holes
This sign is the most typical of a deficiency.
Potassium has the advantage of being unfavourable to algae, unlike phosphate or nitrate: a slight excess does not trigger a bloom, which makes it an easy element to correct. It should still be dosed methodically, because a large excess interferes with the uptake of calcium and magnesium and can end up causing other deficiencies. A weekly test and gradual dosing spare you this imbalance.
Liquid carbon once the potassium has been corrected
In a heavily planted, brightly lit tank, carbon often becomes the limiting element for growth once the major nutrients have been restored. EasyCarbo supplies this carbon in liquid form, with no cylinder or CO2 diffuser. Combined with Kalium, it lets your fast-growing plants make the most of the light without potassium immediately becoming limiting again.
💧 The dosage
Kalium is concentrated: 10 ml in 100 litres raises potassium by 4 mg/L, and this weekly dose is enough in most tanks. If your 200-litre aquarium reads 4 mg/L, you need to add 8 mg/L to reach about 12 mg/L, which means 40 ml spread over the week. Then measure once a week and reduce the dose as soon as the level stabilises.
Add the dose in the morning, when the lighting comes on, and pour it near the filter outlet so that it spreads throughout your tank. After a water change, top up again, because fresh water often contains less than the tank water. The 250 ml bottle treats 2,500 litres, which is nearly 6 months on a 100-litre tank, while the 500 ml bottle suits large, heavily planted tanks, where consumption is higher. Close it after use and keep it away from heat.
🌱 In aquaponics
In aquaponics, potassium is often one of the first nutrients to run short, because fish feed contains little of it compared with what fruiting crops need. Tomatoes, peppers and strawberries demand a lot of it at flowering, whereas lettuces and herbs need less. A dose based on a test result corrects this shortfall without altering the pH.
Start with half a dose and measure after a few days: fish and filter bacteria tolerate potassium well, but an excess does nothing for your plants. Once the level has stayed stable for several weeks in a row, space out the measurements and only test again when you change crop or when fruit appears. The article on deficiencies in aquaponics helps you tell this shortage apart from the others.
Technical specifications
The essentials
- Nutrient supplied
- Potassium (K)
- Supply
- +4 mg/L of potassium for 10 ml in 100 L
- Dosage
- 10 ml per 100 L per week
- Water
- Soft water, planted aquarium
To budget for separately
- Measurement
- Potassium test
- Supplementary fertiliser
- An iron fertiliser if the young leaves turn yellow
In the box
- 1 bottle of Kalium with dosing cap, 250 or 500 ml depending on the size chosen
Supply and dosage stated by the manufacturer Easy-Life, recorded on 13/10/2026.
Which bottle for your tank?
The same fertiliser in two sizes. What sets them apart is the volume treated.
250 or 500 ml?
Answer one question and the table highlights the bottle that suits you.
| Volume treated (L) | Time needed for a 100 L tank | Price | |
|---|---|---|---|
| Recommended 250 mlYour choice | 2500 L | Around 6 months | 5,90 € |
| 500 ml Your choice | 5000 L | Approximately 1 year | 9,50 € |
250 mlRecommended
What the bottle treats
Volume treated (L)2500 L
Time needed for a 100 L tankAround 6 months
500 ml
What the bottle treats
Volume treated (L)5000 L
Time needed for a 100 L tankApproximately 1 year
Volumes and durations calculated on the basis of 10 ml per 100 L per week.
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Frequently asked questions
6 questions
6 key questions
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