The manufacturer Aqua Rebell offers two different complete iron fertilizers for planted tanks, Mikro Basic Eisen and the Mikro Spezial Flowgrow. Many users are wondering which of the two is better for their aquarium. We have put together some tips for you and explain the differences.

Mikro Basic Eisen

As the name of this liquid fertilizer already implies, the Mikro Basic Eisen should be among the basic equipment of a plant aquarium. It is easy to use and suitable for any kind of planted aquarium, be it aquascape, Holland-aquarium with many stem plants or plain and simply a community aquarium with aquatic plants. It contains many important trace elements like iron, but also manganese, boron, molybdenum and cinc. Furthermore it contains the makronutrient potassium. The nutrients in the aquarium fertilizer Mikro Basic Eisen are long-term available. This is due to the so-called complexing agents, with which the nutrients are chelated. EDTA, DTPA and HEDTA as strong chelators make sure, that the nutrients added by the fertilizer remain available to the aquatic plants for as long as possible. For this reason, Mikro Basic Eisen is very suitable for weekly or push fertilization, but can also be used as an everyday fertilizer. Using a suitable water test, the iron content stays permanently traceable. 0,05 to 0,1 mg/l should be a rough benchmark for moderately to densely planted aquarium tanks. For planted aquariums that only see fertilization irregularly or at longer intervals, the Mikro Basic Eisen is a good choice.

You can have a look at the exact nutrient composition here.

Mikro Spezial Flowgrow

The Mikro Spezial Flowgrow is designed to satisfy the higher demands of plant aquarists towards growth and vitality. A high metabolic rate is present especially in bright light aquariums with very intense lighting and many fast-growing plants - due to the fast growth rate of the aquarium plants. Here, on the one hand, a regular supply of nutrients is recommended (ie a daily fertilizer) - but on the other hand, a very fast nutrient availability, too. The soft chelation of the nutrients included in the Mikro Spezial Flowgrow by ascorbate, citrate und gluconate. Note: Due to the fact that aquatic plants and other organisms in the aquarium can quickly absorb the nutrients from this fertilizer, it is possible that elements such as iron are not permanently detectable in the aquarium water. Often the proof is only possible shortly after the immediate addition of the fertilizer. For plant aquariums, iron concentrations of 0.05 to 0.1 mg/l are often recommended, and many users think that these values must be maintained permanently. In case of Mikro Spezial Flowgrow this is not necessary, since the iron is absorbed and stored immediately. If you keep ferting up, the ever-increasing iron value can trigger the growth of red algae. Instead of becoming set on certain target values, you should observe your plants closely. Iron deficiency, in particular, can be seen quite clearly at the leaf tips: Die Triebspitzen werden hell oder verkleinern sich (see: ”Deficiency symptoms in aquatic plants”).

You can have a look at the exact nutrient composition here.

Recommendation for your aquarium

So let's summarize: the Mikro Basic Eisen is suitable for any kind of planted aquarium and demonstrates its strengths with a longer availability of nutrients in “regularly” planted aquarium tanks and only need a weekly fertilization. The Mikro Spezial Flowgrow lends itself for daily use in heavily planted aquariums with intense lighting and offers the benefit of a faster nutritional intake of the plants.
The two fertilizers can even be combined, so you can reap the best from both of them! Mikro Spezial Flowgrow as a daily fertilizer, and Mikro Basic Eisen to fert up the freshwater during the weekly water change.