JBL ProAquaTest K Potassium, Refill

The JBL ProAqua Test K Potassium is a water test for analysis of potassium content in freshwater and seawater aquariums, as well as in the pond.

Potassium is one of the macroelements that is very effectively absorbed and temporarily stored by freshwater plants within a few hours. In growing plants, the potassium requirement is higher compared to other elements. Despite regular fertilization, potassium can, therefore, be reduced to a minimum and the plants can stagnate in growth.

Potassium deficiency leads first to chlorotic sites on the leaf margin, which gradually enlarge and then turn into grey-brown necroses. The leaves can also curl. In Central European tap water, potassium is usually a deficient element compared to natural biotopes, especially in relation to calcium and magnesium concentrations. For good plant growth, the potassium content should be around 10 mg / l, for aquariums with high illuminance (eg so-called scapes) up to 30 mg / l can make sense. Higher potassium levels in the aquarium water favour the growth of green filamentous algae. In seawater, potassium is present in concentrations of 380-400 mg / l, but is consumed only in small quantities.

Too high potassium content can be dangerous for sensitive animals such as shrimp. The potassium content of the aquarium water should first be measured daily. Thus, the needs of the plants can be determined and the dosage of the fertiliser can be made accordingly. Thereafter, routine measurements can be made at longer intervals.

Recommended potassium values:
Freshwater aquarium (community aquarium): 10-30 mg / l
Malawi Lake Tanganyika: 10-30 mg / l
Plant aquariums with few fish (aquascaping): 10-30 mg / l
Marine Aquarium: The potassium content is not measurable with this test

Our expert Oliver Knott recommends:

Inexplicable green algae problems are often the cause of a nutrient over-supply - a water test provides information quickly and safely!