The role of nitrifying bacteria: make aquarium water clear without spending money 1 2 3 4 5 6 A detailed explanation of the application of nitrifying bacteria in aquaculture!
Many people have developed certain misunderstandings about nitrifying bacteria. Some think nitrifying bacteria can decompose feces; some think they can purify water quality and neutralize suspended matter in the water. These understandings are inaccurate, or one could say wrong. So below I will talk about my understanding of nitrifying bacteria.
1. First, let's talk about decomposing organic matter. This rough heavy labor is not something the delicate nitrifying bacteria can accomplish; it is done by other water-purifying bacteria. In the aquatic ecological circulation system, if no other heterotrophic bacteria (note: bacteria that rely on decomposing organic matter to obtain the energy needed for survival) exist, the water will be filled everywhere with organic matter that has not been decomposed by bacteria. Such a self-polluting aquatic environment likewise makes it impossible for fish to survive in it. Therefore, they are often regarded as the vanguard of water self-purification, and their importance is no less than that of nitrifying bacteria. These bacteria are commonly found in all kinds of different environments. They are almost everywhere, and their reproduction speed is quite astonishing. Most heterotrophic water-purifying bacteria, in an ideal environment, need only a few dozen seconds to double themselves, and generally only about twenty-odd minutes to double. But if we keep a bare tank, we must rely on physical circulation to siphon out leftover bait or feces from the water.
2. Regarding the issue of purifying water quality and neutralizing suspended matter in the water. Quite a few fish keepers buy nitrifying bacteria and add them on schedule every week according to the instructions. Is this correct? The answer is completely correct, 100 points. But what I want to tell everyone is that your practice is not wrong, yet your understanding of nitrifying bacteria is mistaken. Because the so-called nitrifying bacteria we buy and add every week are actually photosynthetic bacteria. (Dumbfounded, right!)
Photosynthetic bacteria, commonly known as: B bacteria. Photosynthetic bacteria are a kind of microorganism in water. Because they have photosynthetic pigments (note: pigments capable of photosynthesis, whose role is equivalent to chloroplasts in green plants), including bacteriochlorophyll and carotenoids, they appear pale pink. Photosynthetic bacteria can, under anaerobic and illuminated conditions, use the hydrogen in compounds and carry out photosynthesis that does not produce oxygen.
Photosynthetic bacteria can survive in certain polluted environments and play an important role in purifying water quality. But they will only exert their effect when the living environment and pollutants match their physiological and ecological characteristics; otherwise it is very difficult to achieve the expected result. For example, in a lightless or oxygenated environment, photosynthetic bacteria are very unlikely to be effective.
If photosynthetic bacteria exist in an aquarium, they will absorb and utilize substances such as organic matter or hydrogen sulfide, causing oxygen-consuming heterotrophic microorganisms to become weak due to lack of nutrients, thereby reducing the chance of toxic decomposition products occurring. At the same time, the water quality in the substrate is thereby purified, promoting the healthy growth of the aquatic organisms being kept.
At present, the photosynthetic bacteria sold in the aquarium market are mainly the photoheterotrophic Rhodospirillaceae (rhodospirilaceae), especially species of the genus Rhodopseudomonas (rhodopseudomonas). This kind of photosynthetic bacteria can, under different environmental conditions, use different metabolic modes to effectively purify water quality. Note: photosynthetic bacteria exert their best effect in water with a pH of 8.2-8.6, so they are more suitable for use in seawater aquariums. Therefore this kind of photosynthetic bacteria can only have a short-lived effect, because our fish tank does not have the ideal environment for them to live in. Unless we build an anaerobic filtration zone and also provide lighting.
Now let's get to the main topic and talk about nitrifying bacteria, which everyone is both familiar with and unfamiliar with
1. When it comes to nitrifying bacteria, we are back to the old topic again. To understand nitrifying bacteria, you must first understand what the nitrogen cycle is.
Step one:
Fish excrement and uneaten food will be converted into ammonia (commonly known as ammomia); this is because oxygen-demanding bacteria in these things cause proteins to break down. And ammonia is
toxic.
Step two:
Nitrifying bacteria living in oxygen can convert ammonia into nitrite (NO2); although nitrite contains less toxin, it is still fatally toxic to fish.
Step three:
Nitrite is then converted by a second type of nitrifying bacteria into nitrate (NO3); and this nitrate is almost non-toxic, but sudden or long-term exposure to high concentrations of nitrate is harmful. Fortunately, the concentration of nitrate can be reduced by changing the water in the fish tank.
Step four:
Nitrate is then converted by bacteria that survive without relying on oxygen (anaerobic bacteria) into nitrogen gas and released into the air. This is a complete "nitrogen compound cycle."
2. What are nitrifying bacteria
Nitrifying bacteria, commonly known as A bacteria (nitrifying), are a kind of aerobic bacteria that can grow in oxygenated water or sand layers and play a very important role in the water purification process of the nitrogen cycle. They include morphologically different types of bacilli, cocci or spirilla. They belong to the category of autotrophic bacteria and include two completely different metabolic groups: Nitrosomonas (nitrosomonas) and Nitrobacter (nitrobacter).
Bacteria of the genus Nitrosomonas are generally called "oxidizers of ammonium," because their only food source for survival is ammonium, and the chemical energy generated by the combination of ammonium and oxygen is enough to sustain them. What is ammonium? This needs some explanation. In fact, ammonium is the cation (NH4+) produced when ammonia gas (NH3) dissolves in water. Because its chemical behavior is like that of a metal ion, it is named "ammonium." Gaseous ammonia has a pungent odor, while ionic ammonium has no particular smell, so it is very easy to identify.
When air is present, ammonium can be absorbed and utilized by bacteria of the genus Nitrosomonas. They oxidize its hydrogen atoms into water, replacing them with oxygen, so ammonium becomes water and nitrogen oxide dissolved in water, which chemists call "nitrous acid." The reaction formula is as follows:
Oxidizing ammonium into nitrous acid (NO2-) by means of oxygen can produce energy. Nitrosomonas can use this energy to manufacture organic matter from carbon dioxide or alkalinity (such as co32- or hco3-), so this type of bacteria fundamentally does not need organic matter to survive and reproduce.
Bacteria of the genus Nitrobacter are generally called "oxidizers of nitrous acid," because their main food source for survival is nitrous acid, and the chemical energy generated by the combination of nitrous acid and oxygen is enough to sustain them, and the nitrate produced is the final product of the nitrogen cycle. The reaction formula is as follows:
Nitrobacter can use the energy produced by this reaction to synthesize the organic matter they need, so this type of bacteria likewise can survive and multiply without taking in organic matter.
The reaction in which ammonium is oxidized by nitrifying bacteria into nitrous acid and then subsequently oxidized into nitric acid is called "nitrification" by chemists. This reaction is carried out by two different types of bacteria and requires close coordination so that the intermediate product no2- does not remain and accumulate in the water.
3. How to increase sufficient amounts of nitrifying bacteria?
The toxic substances present in aquaculture ponds are mainly ammonia and nitrous acid. These two toxic substances can be consumed by nitrifying bacteria and produce non-toxic nitric acid, and nitric acid is also the best nitrogen fertilizer for algae and can be absorbed and assimilated by algae. Therefore, nitrifying bacteria are absolutely indispensable in aquaculture ponds. If nitrifying bacteria are lacking, the ammonia content in the water will increase rapidly, putting the fish and shrimp in the pond at risk of death. Many people usually do not understand the importance of this issue, and as a result often suffer the fate of failed aquaculture. This shows that if you do not understand the crux of this problem and seek to improve it, even experienced operators may fail under the harm of insufficient nitrifying bacteria.
From the ecological viewpoint of pond water, we cannot prevent the production of ammonia, but we can try to increase the number of nitrifying bacteria to consume the large amount of ammonia in the pond water. Because nitrifying bacteria are the nemesis that consumes ammonia, as long as the number of such bacteria is sufficient, they will naturally consume the ammonia produced each day, so that ammonia will not accumulate in large amounts in the water and become the invisible killer of aquaculture.
As for what we should do to increase the number of nitrifying bacteria, from a theoretical point of view, creating an ideal breeding place for nitrifying bacteria is the most fundamental solution. How so? It turns out that during reproduction, nitrifying bacteria tend to attach to the outer surfaces of fixed objects. If several fixed objects with large surface area can be placed in the pond water for them to attach to, they can quickly attach to the surfaces of these fixed objects and begin to multiply.
However, placing fixed objects in pond water is usually not feasible, because this method may obstruct the activities of fish and is not conducive to netting them. A more feasible approach is to place "biochemical culture balls" in the filtration system. This product is specially designed to provide a breeding place for nitrifying bacteria. It is usually made of a black plastic skeleton, roughly a hollow sphere with a diameter of 3 ~ 5 cm, and has a very large surface area for nitrifying bacteria to attach to. Its principle is to make nitrifying bacteria into "snails with shells," increasing the living space of nitrifying bacteria, so that nitrifying bacteria can attach to this man-made sphere to carry out nitrification activities, allowing ammonia and nitrous acid in the filtered water to be consumed by nitrifying bacteria.
Adding nitrifying bacteria preparations is another feasible method, especially when water quality testing finds that the ammonia concentration in the water is on the high side; this method is the most efficient. But this method only treats the symptoms, not the root cause, because after these preparations are activated into live bacteria in the water, they are still mostly "shell-less snails" and cannot multiply in the pond water, and may even gradually die due to an unsuitable environment. Therefore they must be added regularly to produce the expected effect.
4. How to correctly use biochemical culture balls?
Biochemical culture balls, also called biochemical filter balls, are a special filter material that removes ammonia by biochemical means. However, it does not rely on the effect of the filter material itself to remove ammonia, but rather relies on nitrifying bacteria living on the surface of the filter material to oxidize ammonia, converting it into non-toxic nitric acid, thereby reducing the accumulation of toxic substances and creating an excellent growing environment for the cultured organisms.
Biochemical culture balls have a vast surface area, and the interlaced mesh structure can achieve a completely ventilated effect on the surface. Moreover, if biochemical culture balls are connected to one another, they can form a huge activity space in the filtration system for nitrifying bacteria to inhabit and live in, and are conducive to the massive reproduction of nitrifying bacteria.
When using this product, it is best to combine it with a mechanical filtration system and not use it alone. That is, after the filtration stage of the mechanical filtration system, add a "biochemical culture ball box" with biochemical culture balls inside, allowing the filtered water to automatically drip down from above, and then through the nitrification process during the dripping, achieve the most perfect biological self-purification effect.
If biochemical culture balls are used alone, the expected effect may not be achieved, because if pond water is directly introduced into the "biochemical culture ball box," the water will inevitably carry quite a lot of organic waste. Since these are not welcomed by nitrifying bacteria, if these organic wastes attach to the biochemical culture balls, it will be very difficult for nitrifying bacteria to settle and grow on their surfaces. Therefore, the organic impurities in the pond water should first be filtered out, and then the filtered water should be introduced into the box. This is the correct way to use it.
5. Use of nitrifying bacteria preparations
Nitrifying bacteria preparations are a treatment agent used to control the concentration of self-generated ammonia in aquaculture pond water. They are not only quite convenient to use, but also can produce an immediate effect, so they are increasingly welcomed by fish keepers. When using them, the agent can be directly scattered in the pond, and before long it can exert its ammonium-removing effect.
Commercially available nitrifying bacteria preparations can be divided into two types: live bacteria and dormant bacteria. Fish keepers can choose and use them according to their own needs. The former is made using the living bodies of bacteria, and their activity can be seen under microscopic observation. The latter is made using dormant bacteria, and under microscopic observation, they cannot be seen to have any activity capability.
The advantage of choosing live bacteria is that the ammonium-removing effect is rapid, and they are most suitable for emergency situations where the ammonia concentration is too high. But because live bacteria have very strict oxygen requirements, especially bacteria of the genus Nitrobacter, which can only survive where sufficient oxygen exists, precisely because of this, preserving live bacteria and making them into products often involves preservation difficulties. Therefore, when purchasing this type of product, special attention should be paid to its effective use period. If an expired product is used, from the viewpoint of ammonium removal, it will also have little efficiency.
The advantage of choosing dormant bacteria is that they can be stored for a long time, and there is less need to worry about the problem of losing effectiveness. However, because the activation time needed for dormant bacteria to become live bacteria may take several days, they cannot be used for handling emergency situations and are only suitable for routine water quality management. Generally speaking, the shelf life of dormant bacteria is about 1 ~ 2 years. When using them, one still needs to pay attention to the use period marked on the product to avoid expiration and loss of effectiveness. In addition, for this type of product, only bacteria of the genus Nitrosomonas can be made into preparations, so after use there may be excess intermediate product no2- remaining and accumulating in the water, causing a temporary sudden increase in the concentration of nitrous acid, but it will not have an obvious impact on water quality
6. Precautions for nitrifying bacteria
There is an organic pollution source in the water. Water-purifying bacteria survive by relying on organic pollution in the water. If there is no pollution source in the water, they cannot survive for long. Therefore, whether adding bacteria at the new water stage is effective is worth discussing.
Do not use simultaneously with disinfectants and bactericides
To avoid water-purifying bacteria being killed, be sure not to use them simultaneously with disinfectants and bactericides. If bactericides or medications for treating fish diseases must be used, wait at least one week or more after using the medication before using water-purifying bacteria.
Pay attention to adjusting the temperature suitable for bacterial growth
During the use of water-purifying bacteria, if the most suitable water temperature conditions can be effectively controlled, then of course the effect they exert is also the most ideal. For example: photosynthetic bacteria can grow and reproduce normally within the range of 23-29°C. When the water temperature is below 23°C, their growth gradually stagnates. Therefore, aquariums below 23°C will have a poorer effect when using this type of bacteria.
Pay attention to adjusting the ph value suitable for bacterial growth
During the use of water-purifying bacteria, attention must be paid to changes in the water's acidity and alkalinity ph. For example: freshwater nitrifying bacteria have the best effect when the ph value is neutral, and the worst effect in acidic water quality. Therefore, if the water quality in the aquarium can be adjusted to neutral or weakly alkaline, its water-purifying effect will be somewhat better. Photosynthetic bacteria are most effective in water with a ph value of 8.2-8.6, so they are more suitable for use in seawater aquariums.
Pay attention to the compatibility among bacteria
If different water-purifying bacteria are to be introduced at the same time, attention should be paid to the compatibility among the bacteria. For example: nitrifying bacteria and photosynthetic bacteria are not suitable for being introduced simultaneously in the same aquarium, because their water purification processes mutually inhibit each other and may reduce their purification effect.
Provide sufficient habitable space for bacteria
If bacteria are only allowed to live in the aquarium, it may not be able to satisfy their reproductive needs, and this will severely limit the number of bacteria so that they cannot increase. Therefore, we should cooperate with a biochemical filtration system to create even more habitable space for the bacteria to reproduce, in the hope that they will accelerate the reduction of harmful substances and strengthen their decomposition ability.
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