Macronutrient fertilizer for aquariums with little or no stock of fish
The three macronutrients n = nitrogen (nitrate), p = phosphorus (phosphate) and k = potassium are particularly important. The addition of N and P is generally not necessary in community aquariums planted normal, because these substances penetrate into the aquarium in sufficient quantities or sometimes even too large via food and fish excrement. On the other hand, the situation is different for demanding planted aquariums or aquascaping aquariums. They have nutritional needs above average, especially with regard to macronutrients. In these types of aquariums, an N or P deficiency can occur quickly, especially with little or no stock of fish. A K deficiency is also possible, but more rarely, because potassium is always present in tap water in a certain quantity and regularly via complete ferrous fertilizers as for example. In the case of demanding planted aquariums, it is therefore completely logical to keep an eye on macro-nutrients and complete them if necessary. One of the most important aspects of an NPK fertilizer is the biological balance of nutrients. The nutrient ratios in Plant Care NPK were chosen so that the three macronutrients are absorbed by plants in the same ratio. This means that even with regular and long -term use, there cannot be deficits or disadvantageous accumulations of individual nutrients. Because nutritional imbalances should always be avoided, as they usually cause algae problems.

When should I use Plant Care NPK?
Each aquarium has a specific consumption of nutrients depending on the quantity of plants, plant species, animal livestock, food, water changes and growth conditions (amount of light/lighting duration, addition of CO 2, filtration technology, etc.). The required addition of NPK must therefore be determined individually for each aquarium. Plant Care NPK is only used when necessary, that is to say when there is a real lack of macronutrients. We recommend measuring the nitrate and/or phosphate content every week and dosing plants NPK accordingly. You can also measure the potassium content of aquarium water (tests in specialized stores). However, this measure is generally not necessary because the tap water plus Plant Care Pro and Plant Care NPK enough potassium is provided. Potassium overdose is hardly possible in practice and is generally not disadvantage. Significant nitrate and phosphate overdoses, on the other hand, can promote the growth of algae. Plant Care NPK should therefore not be used at the beginning without beforehand the nitrate content and ideally also the phosphate content. If the tap water used for water change does not contain an exceptionally high quantity of nitrate or phosphate, later in practice, the only measure of the nitrate content is enough as a basis to decide the fertilization and the NPK dosage. Simple immersion tests can also be used for this, for example the Dennerle Watertest 6in1.
Dosage and application

If you have measured and fertilized regularly for several weeks, you can see what level the measured values ​​stabilize and what additions of macronutrients the aquarium needs. Then you can add the calculated weekly dose of Plant Care NPK as standard and increase the measurement intervals to 2 to 4 weeks in good conscience. A good recommendation is 10 ml/100 l/week, which corresponds to an addition of 5 mg/L of nitrate, 0.4 mg/L of phosphate and 2.5 mg/L of potassium. If the tap water used to change water contains an exceptionally high level of nitrate (for example 50 mg/l) but little phosphate or high phosphate levels (> 1 mg/l) but little nitrate, then Plant Care NPK must be used to avoid high levels of individual macronutrients and nutritional imbalances. In this case, the fertilizers of the Plant Care N or Plant Care P should be used to specifically compensate for nutrient deficiencies. Because in addition to the absolute concentration of nutrients, nutrient ratios are also important. The nitrate report on phosphate should ideally be between 10: 1 and 15: 1. If tap water contains only small amounts of potassium (for example <3 mg/l), Dennerle Plant Care Kêtre used. This is often the case with very soft water. You can find the analysis values ​​of your own tap water from the local water supplier. They are easily accessible via the Internet. In addition, potassium is one of the rare nutrients that reach the aquarium only in the state of traces via fish food. A macronutrient fertilizer should always be used in combination with a micronutrient fertilizer. For a complete nutrient supply and the best possible growth in plants, we recommend combining plant care npk with Plant Care Pro.
Macro-nutrients, guidelines for planted aquariums