Yes, we noticed that too!

This applies both to the instructions of the aquatic plant fertilisers and sometimes also to recommendations in the relevant iron test sets.

However, there is a good reason why we generally recommend a lower iron content:

• The half-life of iron (and other minerals, for which iron is measured in a representative capacity as it is the easiest to detect) depends on various factors in the aquarium.
• It is a property of high-quality fertiliser products, like those of our company, to have as long a half-life as possible.
• At the end of the recommended dosage period, iron must still be detectable, because gaps in supply may lead to growth stagnation. The longer the recommended period is, the greater the initial concentration must be.
• A long half-life is achieved by using high quality (and expensive) chelators and at least the molar amount of chelators.
• Simpler (and cheaper) products which for cost reasons do not involve these chemical-technical measures have a correspondingly shorter half-life (service life) in the aquarium.
• However, a shorter service life requires a higher initial value to guarantee a corresponding iron content at all times.

As an excessive iron content greatly encourages the growth of certain algae (such as brush algae) but minimal quantities of iron are sufficient for tall plants, it is advisable to achieve a lowest possible but even iron content.
Iron content which fluctuates greatly over the course of a week is also not ideal for excellent plant growth.

This can be supported by the regular addition of a high quality aquarium plant fertiliser (such as Ferrdrakon and KramerDrak) or with an ideal dosage system (Ferrdrakon Power and KramerDrak Power).