For your fish and plants to live in a healthy and vibrant environment, your aquarium must be kept in balance. As in nature, reaching equilibrium necessitates paying attention to numerous elements that maintain the ecosystem’s stability.
This delicate balance is influenced by a number of factors, including light, water quality, and the proper mix of fish and plants. Smallest adjustments can have a big impact and cause problems like stressed fish or an overgrowth of algae.
To create a harmonious underwater world, you can make small, regular adjustments based on your understanding of how these elements interact. This post will discuss useful advice for keeping your aquarium’s equilibrium just right.
In order to create a stable environment where fish, plants, and water conditions all support one another, an aquarium must be balanced. It’s critical to correctly manage elements like water quality, light, and feeding schedules in order to preserve this equilibrium. A healthy and vibrant ecosystem grows in your aquarium when everything is in balance, which lowers the likelihood of issues like stressed fish or an overgrowth of algae.
- Biological water purification
- 1.2. Nitrification of water.
- Video on the topic
- The balance in the aquarium is restored, the algae retreat #NIK_72
- NITROGEN CYCLE. THE WHOLE MECHANISM AS IT IS
- How to establish balance in the aquarium?/Launch 150 liters
- Biobalance in the aquarium. What is it? Aquarium keeping for beginners
- #Nitrogen cycle, #BIO balance, #bacteria in the aquarium. Theory, practice of application and personal experience.
- HOW TO ACHIEVE CRYSTAL CLEAR WATER IN THE AQUARIUM I SHARE SECRETS!
Biological water purification
Among the most significant procedures that take place in enclosed aquarium systems is biological water purification. By "biological purification," we mean the process by which bacteria that reside in the water column, gravel, and filter detritus mineralize, nitrify, and assimilate nitrogen-containing compounds. These kinds of organisms are consistently found in the filter column. Nitrogen-containing materials change forms during the mineralization and nitrification processes, but nitrogen stays in the water. Only during the denitrification process does the solution lose nitrogen (see section 1.3).
Aquarium water can be purified using four different methods, one of which is biological filtration. The following section covers the other three techniques: physical adsorption, mechanical filtration, and water disinfection.
Figure 1.1 depicts the water purification scheme, while Figure 1.2 depicts the nitrogen cycle in an aquarium, which includes the nitrification, denitrification, and mineralization processes.
The role of biological purification in the water purification process is shown in Fig. 1.1. Biological purification, mechanical filtration, physical sedimentation, and disinfection are done from left to right.
The nitrogen cycle in closed aquarium systems is shown in Fig. 1.2.
1.1. The mining process.
The two primary categories of microorganisms found in aquariums are autotrophic and heterotrophic bacteria.
Note: Not from the book by the author.
Heterotrophs are organisms that cannot produce organic matter from inorganic matter through photosynthesis or chemosynthesis (dr. Greek: "other," "different," and "food"). They need exogenous organic substances, or those made by other organisms, in order to synthesize the organic substances required for their essential activity. Digestion enzymes convert organic polymers into monomers during the digestion process. Heterotrophs are reducers and consumers of different orders in communities. Heterotrophs include almost all animals and some plants. They are split into two opposing groups based on how they obtain food: holozoans, which are animals, and holophytes, also known as osmotrophs, which are bacteria, fungi, plants, and many protists.
Autotrophs are organisms that synthesise organic substances from inorganic materials (ancient Greek: sam + food). In the food pyramid, autotrophs occupy the top tier (the first links of food chains). In the biosphere, they are the main producers of organic matter, which serves as food for heterotrophs. It should be mentioned that there are situations in which it is impossible to distinguish clearly between autotrophs and heterotrophs. Euglena green, a single-celled algae, is an example of an autotroph that is a heterotroph in the dark.
Though they don’t always line up, the ideas of "autotrophs" and "producers," as well as "heterotrophs" and "consumers," are occasionally confused. As an illustration, blue-green algae, or Cyanea, have the ability to produce organic matter on their own through photosynthesis and then consume it in its completed form, breaking it down into inorganic substances. As such, they are simultaneously producers and reducers.
In order to construct their bodies, autotrophic organisms use inorganic materials found in the soil, water, and air. In this instance, carbon comes primarily from carbon dioxide. In this instance, some of them (phototrophs) get their energy from the Sun, while others (chemotrophs) get their energy from inorganic compound reactions.
Aquatic animal excretions containing organic nitrogen are used as a source of energy by heterotrophic species, who then use these components to create simple compounds like ammonium (which is the total of ammonium ions (NH4+) and free ammonia (NH3), which is measured analytically as NH4-N). The initial step in biological treatment is the mineralization of these organic materials.
The breakdown of proteins and nucleic acids and the creation of amino acids and organic nitrogenous bases can initiate the mineralization of nitrogen-containing organic compounds. Ammonium is formed through the mineralization process of deamination, which involves the splitting off of the amino group. The breakdown of urea to produce free ammonia (NH3) can be the topic of deamination.
A chemical reaction of this kind can happen, but bacteria are needed for the deamination of amino acids and other related compounds.
1.2. Nitrification of water.
"Nitrification" is the next stage of biological treatment that occurs after heterotrophic bacteria have transformed organic compounds into inorganic form. It is believed that ammonium is being biologically oxidized to nitrites (NO2-, calculated as NO2-N) and nitrates (NO3, calculated as NO3-N). The primary agents of nitrification are autotrophic bacteria. Autotrophic organisms, in contrast to heterotrophic ones, have the ability to absorb inorganic carbon (primarily CO2) in order to build their own cells.
In freshwater, brackish, and marine aquariums, autotrophic nitrifying bacteria are primarily found in the genera Nitrosomonas and Nitrobacter. Ammonium is oxidized to nitrites by Nitrosomonas, and nitrites to nitrates by Nitrobacter.
Energy absorption causes both reactions to happen. The transformation of toxic ammonium into considerably less toxic nitrates is the meaning of equations (2) and (3). The presence of toxicants in the water, temperature, the amount of dissolved oxygen in the water, salinity, and the filter’s surface area all affect how effective the nitrification process is.
Toxic materials. Numerous substances can prevent nitrification in specific situations. These compounds either inhibit the growth and reproduction of bacteria in water or interfere with their intracellular metabolism, preventing them from oxidizing.
In freshwater aquariums, the nitrification processes are not affected by many antibiotics and other products used to treat fish, while some prove to be toxic to varying degrees, according to reports from Collins and co-authors (Collins et al., 1975, 1976) and Levine and Med (Levine and Meade). Studies in seawater were not conducted in parallel, and marine systems should not be subjected to the above results.
The table displays the information provided in the three indicated works. 1.1. Because different research methodologies were employed, some research findings cannot be fully compared.
Table 1.1 shows how nitrification in freshwater aquariums is affected by therapeutic norms for dissolved antibiotics and medicinal drugs (Collins et al., 1975, 1976, Levine And Meade, 1976).
Collins et al. investigated the effects of pharmaceuticals in water samples extracted straight from fish-keeping working pools equipped with biofilters. For their studies, Levine and Mead employed pure bacterial cultures. Their techniques seemed to be more sensitive than standard ones. Accordingly, formalin, malachite green, and nifurpirinol exhibited a moderate level of toxicity for nitrifying bacteria in their experiments, although Collins et al. demonstrated that the same preparations were safe. Levine and Mead postulated that the disparities resulted from the higher concentration of autotrophic bacteria in pure cultures and that the inactivation threshold would rise with the concentration of dissolved organic matter and the presence of heterotrophic bacteria.
It is evident from the data in Table 1.1 that sulfanilamide, methylene blue, erythromycin, and chlorotetracycline have clearly expressed toxicity in fresh water. Of the substances examined, methylene blue proved to be the most toxic. Testing potassium permanganate and chloramphenicol yielded inconsistent results.
Levine and Mead concur as well as Collins et al. that copper sulfate does not considerably prevent nitrification. The binding of free copper ions to dissolved organic compounds could be the cause of this. According to Tomlinson et al. (1966), Nitrosomonas was significantly more sensitive to the effects of heavy metal ions (Cr, Cu, and Hg) in pure culture as opposed to activated sludge. They proposed that the development of chemical complexes between metal ions and organic matter was the cause of this. Short-term exposure to heavy metals was less effective than long-term exposure, most likely due to the incomplete utilization of organic molecules’ adsorption bonds.
Temperature. Many bacterial species can tolerate wide temperature fluctuations, although their activity is temporarily reduced. The adaptation period, called temporary temperature inactivation (TTI), often occurs with sudden changes in temperature. Usually, VTI is noticeable when the water is suddenly cooled; an increase in temperature usually accelerates biochemical processes and therefore the adaptation period may go unnoticed. Srna and Baggaley (1975) studied the kinetics of nitrification processes in marine aquariums. An increase in temperature by only 4 degrees Celsius led to an acceleration of ammonium and nitrite oxidation by 50 and 12%, respectively, compared to the initial level. With a decrease in temperature by 1 degree Celsius, the rate of ammonium oxidation decreased by 30%, and with a decrease in temperature by 1.5 degrees Celsius, the rate of nitrite oxidation decreased by 8% compared to the initial conditions.
Water’s pH. Nitrification is suppressed more in seawater than in freshwater at pH values lower than 9, according to research by Kawai et al. (Kawai et al., 1965). They explained this away as freshwater’s naturally lower pH. A drop in pH inhibits ammonium oxidation in freshwater aquariums, according to Saeki (1958). The ideal pH for nitrite oxidation is 7.1 and for ammonium oxidation is 7.8. According to Seki, a pH range of 7.1–7.8 is ideal for nitrification. Marine nitrifying bacteria were most active at pH 7.45 (range 7-8.2), according to Srna and Baggaley’s research.
Dissolved oxygen in water. A biological filter can be compared to a huge breathing organism. When working properly, it consumes a significant amount of oxygen. The oxygen needs of aquatic organisms are measured in units of BOD (biological oxygen demand). The BOD of a biological filter is partly dependent on nitrifiers, but is mainly due to the activity of heterotrophic bacteria. Harayama (1965) showed that at high BOD, a large population of nitrifiers was active. He passed seawater through a sand layer of an operating biological filter. Before filtration, the oxygen content in the water was 6.48 mg / l, after passing a 48 cm thick layer of sand. it decreased to 5.26 mg/l. At the same time, the ammonium content decreased from 238 to 140 mg.eq./l., and nitrites – from 183 to 112 mg.eq./l.
Both aerobic (need O2 for life) and anaerobic bacteria (do not use O2) are present in the filter layer, however, aerobic forms predominate in well-aerated aquariums. In the presence of oxygen, the growth and activity of anaerobic bacteria are suppressed, so normal circulation of water through the filter restrains their development. If the oxygen content in the aquarium decreases, either an increase in the number of anaerobic bacteria occurs, or a transition from aerobic to anaerobic respiration occurs. Many products of anaerobic metabolism are toxic. Mineralization can also occur with reduced oxygen content, but the mechanism and end products in this case are different. Under anaerobic conditions, this process is more enzymatic than oxidative, with the formation of organic acids, carbon dioxide and ammonium instead of nitrogenous bases. These substances, along with hydrogen sulfide, methane and some other compounds, give the suffocating filter a putrid smell.
Salinity. Many types of bacteria can survive in waters with large ionic composition fluctuations as long as the salinity variations happen gradually. The majority of the bacteria that ZoBell and Michener (1938) isolated from seawater in their lab could also grow in freshwater. Even direct transplantation of many bacteria was successful. By dilution with seawater, all 12 species of bacteria that are thought to be exclusively "marine" were successfully brought to freshwater (5% fresh water was added each time).
Bacteria of the biological filter are very resistant to fluctuations in salinity, although if these changes are significant and sudden, bacterial activity is suppressed. Srna and Baggaley (1975) showed that a decrease in salinity by 8% and an increase by 5% did not affect the rate of nitrification in marine aquariums. At normal salinity in marine aquarium systems, the nitrifying activity of bacteria was highest (Kawai et al., 1965). The rate of nitrification decreased with both dilution and concentration, although some activity remained even after the salinity of the water was doubled. In freshwater aquariums, bacterial activity was highest before the addition of sodium chloride. Immediately after the salinity became equal to that of seawater, nitrification ceased.
There is proof that salinity influences both the amount of end products produced and the rate at which nitrification occurs. Although more nitrite and nitrate were formed in marine aquarium systems, Kuhl and Mann’s (1962) research demonstrated that nitrification occurred more quickly in freshwater aquarium systems. Similar findings were obtained by Kawai et al. (Kawai et al., 1964), and they are displayed in Fig. 1.3.
Figure 1.3 shows the number of bacteria in the filter bed after 134 days in small freshwater and marine aquarium systems (Kawai et al., 1964).
Filter surface area. Kawai et al. found that the concentration of nitrifying bacteria in the filter was 100 times higher than in the water flowing through it. This demonstrates the importance of the contact surface area of the filter for nitrification processes, since it provides the opportunity for bacteria to attach. The largest surface area of the filter bed in aquariums is provided by gravel particles (ground), and the nitrification process occurs mainly in the upper part of the gravel filter, as shown in Fig. 1.4. Kawai et al. (1965) determined that 1 gram of sand from the upper layer of the filter in marine aquariums contains 10 to the 5th power of ammonium oxidizing bacteria 10 to the 6th power of nitrate oxidizing bacteria. At a depth of only 5 cm. the number of microorganisms of both types decreased by 90%.
Yoshida (1967) published Fig. 1.4, which shows the concentration (a) and activity (b) of nitrifying bacteria in a marine aquarium at various filter depths.
The shape and size of the gravel particles are also important: small grains have a larger surface area for bacteria to attach to than the same amount by weight of large gravel, although very small gravel is undesirable because it makes water filtration difficult. The relationship between their sizes and surface areas can be easily demonstrated with examples. Six cubes weighing 1 gram each. Have a total of 36 surface units, while one cube weighing 6 grams. Has only 6 surfaces, each of which is larger than the individual surface of a small cube. The total area of six one-gram cubes is 3.3 times greater than the surface area of one 6-gram cube. According to Seki (Saeki, 1958), the optimal particle size of gravel (soil) for filters is 2-5 mm.
Compared to rounded particles, angular particles have a greater surface area. All other geometric shapes are larger than the sphere in terms of surface area per unit volume.
Buildup of debris (The word "detritus," which comes from the Latin detritus, which means "weary out," has multiple definitions: 1. Dead organic matter, which is momentarily cut off from the biological cycle of nutrients and includes things like vertebrate bones, invertebrate remains, and excrement; 2. a collection of tiny, partially decomposed plant and animal particles suspended in water or settling on the reservoir bottom; these particles add surface area to the filter and enhance nitrification. Seki claims that bacteria living on detritus is responsible for 25% of the nitrification that occurs in aquarium systems.
1.3. Absorption
The nitrification process leads to a high degree of oxidation of inorganic nitrogen. Dissimilation, "nitrogen respiration", or the process of recovery, develops in the opposite direction, returning end products of nitrification to a low degree of oxidation. In terms of total activity, oxidation of inorganic nitrogen significantly exceeds its reduction, and nitrates accumulate. In addition to dissimilation, which ensures the release of part of the free nitrogen into the atmosphere, inorganic nitrogen can be removed from the solution by regularly replacing part of the water in the system, by assimilation by higher plants or using ion exchange resins. The latter method of removing free nitrogen from the solution is applicable only in freshwater (see. section 3.3).
The process of dissimilation is primarily anaerobic and takes place in filter layers that are low in oxygen. Denitrifiers with the ability to reduce, bacteria are typically either fully (obligate) anaerobes or aerobes that can transition to anaerobic respiration in the absence of oxygen. These are typically heterotrophic organisms; for instance, some Pseudomonas species have the ability to reduce nitrate ions (NO3-) in the presence of oxygen scarcity (Painter, 1970).
During anaerobic respiration, dissimilatory bacteria assimilate nitric oxide (NO3-) instead of oxygen, reducing nitrogen to a compound with a low oxidation number: nitrites, ammonium, nitrogen dioxide (N20) or free nitrogen. The composition of the final products is determined by the type of bacteria involved in the reduction process. If inorganic nitrogen is completely reduced, that is, to N2O or N2, the dissimilation process is called denitrification. In a fully reduced form, nitrogen can be removed from water and released into the atmosphere if its partial pressure in the solution exceeds its partial pressure in the atmosphere. Thus, denitrification, unlike mineralization and nitrification, reduces the level of inorganic nitrogen in water.
A "balanced" aquarium (1.4).
"A balanced aquarium" is a system in which the activity of bacteria inhabiting the filter is balanced with the amount of organic energy substances entering the solution. The level of nitrification can be used to judge the “balance” and suitability of a new aquarium system for keeping aquatic organisms – hydrobionts. Initially, the limiting factor is the high ammonium content. Usually in warm-water (above 15 degrees Celsius) aquarium systems it decreases after two weeks, and in cold-water (below 15 degrees) – over a longer period. The aquarium can be ready to receive animals during the first two weeks, but it is not yet completely balanced, since many important groups of bacteria have not yet stabilized. Kawai et al. described the composition of the bacterial population of a marine aquarium system.
1. Cardiovascular. Within two weeks of planting the fish, their number multiplied tenfold. Ten to the eighth power of organisms in one gram is the maximum number. After two weeks, filter sand was observed. The bacterial population reached a stable level of 10 to the seventh power of specimens per 1 g after three months. Sand should be filtered.
2. Ammonifiers, bacteria that break down proteins.In just four weeks, the starting density (10 to the power of 3 specimens/gr) increased 100 times. The population reached a stable level of 10 to the power of 4 specimens/gr after three months. The introduction of fresh fish, which is high in protein, as feed led to a notable surge in the population of this particular class of bacteria.
3. Bacteria that break down carbohydrates in starch. 10% of all the bacteria in the system were present at the beginning. After that, it increased gradually until, four weeks later, it started to decline. After three months, the population reached 1% of the total number of bacteria and stabilized.
4. Nitrifying bacteria. The maximum number of nitrite-oxidizing bacteria was noted after 4 weeks, and the “nitrate” forms – after eight weeks. After 2 weeks, there were more “nitrite” forms than "nitrate". The number stabilized at 10 to the 5th power and 10 to the 6th power of specimens. accordingly. There is a time difference between the decrease in ammonium content in water and oxidation at the beginning of nitrification, due to the fact that the growth of Nitrobacter is suppressed by the presence of ammonium ions. Efficient oxidation of nitrites is possible only after most of the ions have been converted by Nitrosomonas. Similarly, the maximum of nitrites in the solution should appear before the accumulation of nitrates.
A new aquarium system’s high ammonium content may be brought on by fluctuations in the amount of autotrophic and heterotrophic bacteria present. When a new system is first coming into operation, heterotrophic organisms grow faster than autotrophic forms. Certain heterotrophs take up a large amount of the ammonium that is created during mineralization. Put differently, it is impossible to discern between ammonium processing that is heterotrophic or autotrophic. Only after the number of heterotrophic bacteria has decreased and stabilized does active oxidation by nitrifying bacteria take place (Quastel and Scholefield, 1951).
A new aquarium’s bacterial population is only significant until it reaches a stable number for each kind. Subsequently, variations in the energy substance supply are offset by an increase in the metabolic activity of individual cells without a corresponding increase in cell number.
The population density of nitrifying bacteria living in a filter of a particular area is relatively constant and is independent of the concentration of incoming energy substances, according to research by Srna and Bagaliya and Quastel and Shoelfield (1951).
The daily supply of oxidizable substrate is directly correlated with the total oxidizing capacity of bacteria in a balanced aquarium. Ammonium and nitrite levels in the water noticeably rise in response to abrupt increases in the weight, number of animals being raised, and amount of feed added. Until the bacteria adjust to the new environment, this state of affairs continues.
The length of the elevated nitrite and ammonium content period is determined by the additional load placed on the water system’s processing component. After three days in warm water and much longer in cold water, the biological system usually reaches equilibrium under new conditions provided it is not beyond its maximum productivity. The ammonium and nitrite content will rise steadily if the extra load is greater than what the system can handle.
The processes of minerality, nitrification, and denitrification happen in a new aquarium in roughly that order. In a well-established and stable system, they happen nearly at once. The ammonium content (NH4-N) in a balanced system is less than 0.1 mg/l, and denitrification is the cause of all captured nitrites. The aforementioned processes move forward in unison, never falling behind, because all incoming energy sources are swiftly absorbed.
This content is taken from S.Spott’s book "Keeping Fish in Closed Systems," which can be viewed in its entirety at this link.
Here are the basic chains of biological equilibrium that immediately came to my mind. There are many examples of such chains: with fish and snails, with fish, snails and plants, with fungi, bacteria and fish, and so on … almost ad infinitum. Moreover, you must understand that these chains are not linear. That is, the chain NH3 / NH4 – NO2 – NO3 – N2 is a template. Nitrite can be reduced back to nitrite (denitrification). Ammonia can be spent anywhere, not only along the template chain. Imagine that an aquarium is a huge borscht. carrots, onions, beets. Well, or compote, if you like. And all this brew is cooked every second.
Based on the information provided, we can define aquarium BIOBALANCE IN A BROAD SENSE as the entirety of all biological chains and linkages.
The bio-formation process, which is still subdivided into:
– Biological chains, or the direct communication between living things (bio);
– attributes, elements, and instruments, i.e., parts that directly impact how well living things interact. These comprise the following: soil, "interior," lighting level and quality, filtration quality, water parameters (DH, KH, PH, RH, and T), etc.
Considering everything that has been discussed, it is critical to realize that "properties, factors, and tools" are significant. Actually, we can configure and modify the biological balance in our pond using these mechanisms. Success is the result of their rejection and adjustment. Conversely, failing to use these instruments compels "nature" to incorporate additional systems in order to preserve equilibrium. The same algae, since, in reality, what is harmful and unpleasant is the aquarium’s response to either too much or too little light or to a high concentration of toxins (NH3, NO2, NO3), etc.
Even seemingly insignificant factors can have a significant impact. For instance, when novices disregard compatibility rules and aquarium population norms, the "destruction of excess" function is activated, resulting in stressed out fish, weakened immunity, the growth of pathogenic bacteria and fungi, and the illness and death of "extra" fish.
In conclusion, we can state that
Aspect | Explanation |
Water Quality | Regularly test and adjust pH, ammonia, and nitrate levels to keep the environment healthy. |
Filtration | Ensure your filter is properly sized and maintained to remove waste and keep water clean. |
Lighting | Provide adequate light without overexposure to prevent algae growth and stress in fish. |
Feeding | Avoid overfeeding to prevent excess waste, which can disrupt the balance. |
The health and welfare of the fish kept in an aquarium depend on the aquarium’s ability to maintain equilibrium. It needs consistent maintenance procedures, thoughtful plant and fish selection, and routine water quality monitoring.
You can establish a setting where all the components function harmoniously by being aware of the requirements of the ecosystem in your aquarium. This guarantees a healthy aquatic life and also transforms the aquarium into a lovely and soothing addition to your room.
Recall that maintaining equilibrium in an aquarium requires constant work. You can have a balanced, healthy aquarium that brings you joy if you have patience and pay attention to detail.