Cloudiness after filling in the water Photo: Moritz Hertel
Depending on the floor used, the water may become very cloudy during or after the water has been put in. Gravel or sand that has been carefully washed out before setting up the aquarium also contains many small particles that are washed up by the water. Any soil fertilizer used also contains particles that can cloud the water.
Some of this turbidity settles again over time, and most of it is filtered out by the filter. Depending on the initial turbidity, a rough filter cleaning makes sense in the first few days so that the filter does not become clogged too quickly. If the turbidity does not decrease significantly over the course of several days, the filter may already be clogged and the filter may need to be cleaned.
What is retraction in an aquarium?
Pollutants enter the aquarium water through the feeding of the fish, the fish excrement, etc. These contaminants are harmful to fish and will result in fish death if there are too many contaminants. Certain bacteria break down some of the pollutants, and some of the pollutants are removed by changing the water. In a freshly set up aquarium there are very few bacteria that break down pollutants. An aquarium is run-in when the bacteria have multiplied so much that they break down so many pollutants that the pollutant content of the water remains harmless for the aquarium inhabitants between water changes.
Which pollutants are produced?
The most well-known pollutant in the aquarium is nitrite, which is toxic to fish. Even a nitrite value of more than 0.1 mg/L can damage fish. In addition, ammonia, which is even more toxic to fish, is formed at high pH values of around 8 and above. At values below 8, some of the ammonia converts to less toxic ammonium. Nitrate can also become harmful if there are more than 50 mg/L in the water. If the pollutant values are too high, the pollutant content must be reduced immediately with water changes and brought to non-hazardous areas. Ammonia and nitrate are partially consumed by the plants as nutrients. The substances are invisibly dissolved in the water.
How are the pollutants measured?
In the aquarium trade there are water tests with which the nitrite value and the ammonia value can be measured. The nitrate test is usually sufficient. With high pH values, an ammonia test makes sense.
Where do the bacteria come from?
Tap water is not completely sterile and contains many bacteria. There are also numerous bacteria in the dust in the air, on all objects. They are spread through touch, air currents, breathing, etc. Bacteria can also be found in the sand or gravel. So many different bacteria get into the aquarium without any special effort. The desired bacteria then multiply in the filter.
What do the pollutant-degrading bacteria in fresh, clean tap water feed on?
Even the tap water contains nutrients for the bacteria. In addition, some flake food can be added to the aquarium at the beginning to feed the bacteria. Leaves falling off the plants bring more food for the bacteria into the water. Snails that may have gotten into the aquarium with the plants also produce bacterial food.
How is the aquarium brought in?
When setting up a new aquarium, the aquarium is completely set up, plants are used and water is filled in. The aquarium is put into operation without adding any fish.
Cloudiness after filling in the water Photo: Moritz Hertel
Through the decomposition of organic substances, e.g. B. dying plant leaves, forms ammonium. Ammonium is taken up by certain bacteria, which process the ammonium and finally excrete nitrite, which is toxic to fish. Nitrite is also taken up and processed by bacteria, which in turn excrete nitrate. The bacterial species involved in each case only multiply if the required food, i.e. ammonium and nitrite, is available in sufficient quantities. The bacteria settle primarily in the filter, but also in the substrate.
During the break-in period, the nitrite value is measured daily. At the beginning the nitrite level is low, but increases slowly and steadily. The more the ammonium-degrading and nitrite-producing bacteria multiply, the faster the nitrite value rises. At the same time, the nitrite-degrading bacteria receive more and more food and multiply themselves. After about 3 to 4 weeks, so many nitrite-degrading bacteria have settled in the filter and in the substrate that they degrade more nitrite than is newly produced. The measured nitrite value starts to decrease.
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As soon as no more nitrite can be determined in the daily measurements, the running-in is complete. From this point in time, there are so many nitrite-degrading bacteria in the aquarium that no dangerous concentrations of pollutants arise with weekly water changes of approx. 30% water between the individual water changes. Nevertheless, the nitrite value should be monitored for a while.
It is sometimes recommended to put a few fish in the aquarium to get used to it and then gradually increase the stock. The metabolism of the first fish and their excretions then stimulate the multiplication of the bacteria. This method is only suitable for experienced aquarists who can quickly recognize and react correctly when problems arise in the aquarium. Beginners should definitely observe the break-in period and only use a few fish after the break-in period in order to then increase the fish stock step by step.
Forage during the break-in phase
The turbidity is receding Photo: Moritz Hertel
It is often recommended to give food to the aquarium from time to time during the start-up phase. As food for the desired bacteria, a very small pinch of finely grated flake food is added to the aquarium about every 2 days. In this case, a lot doesn’t help much. Too much food starts to go moldy. Organic matter enters the aquarium through the food.
Not only flake food is suitable as a food source for the bacteria, but z. B. also food tablets. The protein value is particularly important. Therefore, frozen mosquito larvae, feed granules and the like can also be used. The food should be rubbed as small as possible so that it dissolves quickly and no mold grows. It is also possible to add some ammonium from a chemical store or pharmacy directly to the water to help you get started.
It is unclear whether this method brings any real advantage. Some aquarists are of the opinion that aquariums that are established in this way are significantly more stable than other aquariums. Other aquarists dispute the effect. The running-in time is not significantly reduced. Systematic and meaningful investigations are not known.
What is the nitrite peak?
If you enter the results of the daily nitrite measurements during the running-in period in a graph or coordinate system (x-axis = days, y-axis = nitrite value), the result is a curve that rises slowly at first, then becomes increasingly steeper, and then again after reaching a highest point falls off. The shape of the overall curve resembles a bell or a mountain (English: peak). The highest point of the curve, i.e. the largest measured nitrite value, is the so-called nitrite peak. Since the maximum value varies between aquariums, no absolute number can be given as the maximum value. However, the value can rise to more than 1 mg/L, i.e. to absolutely deadly values for fish. For this reason, never introduce fish before the successful run-in.
Analogously to the nitrite peak, there is also an ammonium peak and a nitrate peak.
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When did the aquarium move in?
The aquarium is running in when the nitrite value has increased and, after reaching a maximum value, has fallen so far that no more nitrite can be determined by measurements. During this time, food must continue to be added to the aquarium. If the nitrite value does not increase, or if the value does not fall below the detection limit again after reaching a maximum value, the amount of feed should be increased carefully. It is possible that the bacteria are not receiving enough nutrition and are therefore not active enough. Only when, despite feeding, the nitrite value drops after reaching a maximum value and finally no more nitrite can be detected, do the bacteria work as required.
How long does it take to drive in?
Experience has shown that it takes about 3 to 4 weeks to break in a newly set up aquarium. The increase in nitrite often begins after about 14 days. The nitrite peak is often between the 21st and 24th day. After about 4 weeks, there are usually no longer any increased nitrite values. In small aquaria, the nitrite peak can be between the 10th and 15th day. Other information assumes approx. 10 days to the ammonium peak and approx. 30 days to the nitrite peak. Since the duration cannot be precisely predicted, without measurements it makes sense to wait 6 weeks to be on the safe side before introducing the first fish. If the nitrite value is measured regularly during the break-in period, fish can be used if the nitrite value has dropped to zero after reaching the nitrite peak.
Finally use fish
The cloudiness is gone the next morning Photo: Moritz Hertel
After the break-in period, fish can be used. But even then, not too many fish should be used at once. At first only a few fish are used and then the stock is slowly increased step by step. First, the more robust fish species are used, more sensitive species only later. It is often recommended to use algae-eating species at the beginning. If such species are to be cared for in the long term, this can certainly be done. However, there is no fish species that really noticeably reduces algae growth.
Depending on the size of the aquarium, 2 to 4 medium-sized fish, e.g. B. Guppy, are also used. As a result, the pollution of the aquarium with organic material is only slowly increased and the bacterial cultures can adapt to the increasing amount of pollutants, ie multiply accordingly. If you stock too many fish too quickly, there is still a risk that more pollutants will be produced than can be broken down. For this reason, the nitrite value will continue to be measured until the aquarium has been running for a few weeks with the stock that was ultimately intended, without the nitrite values being measured too high. If the nitrite values are too high, the stocking is probably too high. This problem can be solved in the short term by changing the water more frequently, but in the long term the stocking must be reduced.
Careful…