Getting past the misconception that water clarity is related to nitrifying bacteria

     Fish keeping is a science. With the popularization of the concept of scientific fish farming, people are paying more and more attention to the fish tank ecosystem, biochemical filtration, biological filter media, nitrifying bacteria, etc., and they are all trying to create a comfortable living environment for the fish, so that they can show their beautiful side to us. But many fish friends have misunderstanding about nitrifying bacteria, I will give you two examples:

Example 1: Why does the water get muddy after I clean the filter media?

A: The biological system is damaged after cleaning the filter media, and the nitrifying bacteria die in large numbers, so the water becomes mixed.

Example 2: Why has the water been rather cloudy and unclear since I started the tank?

A: This is because the biological system is not sound, the number of nitrifying bacteria is relatively small, so the water is not clear, when the nitrification system is sound water is naturally clear.

        Both of these cases are talking about the relationship between water clarity and biological systems (bioflora), so if you think that both of these answers are correct, then be sure to read through this article, because both of them are wrong.

        First of all, let's look at my definition of a nitrification system: a water filtration system that uses biological filter media as a carrier to cultivate nitrifying bacteria is called a nitrification system.From this definition it can be seen that the nitrification system is made up of three main elements: the pump, the biofilter material and the nitrifying bacteria.In fact, the nitrification system is a platform to cultivate nitrifying bacteria, the biofilter material provides nitrifying bacteria with a place to live and reproduce, the water circulation system brings oxygen and food to nitrifying bacteria, and its ultimate goal is to cultivate nitrifying bacteria to remove toxins from the water.

　　    Having understood what the nitrification system is, let's look at its relationship with water clarity. We all know that the function of the nitrification system (nitrifying bacteria) is to purify water, but many people misunderstand the meaning of water purification, and understand water purification as clear water, always linking the clarity of water with the nitrification system (nitrifying bacteria), so there are these two wrong answers above.

　　    The purpose of nitrifying bacteria is to remove toxins (ammonia and nitrites) from the water to purify the water, not to clean it. If the presence of ammonia and nitrites causes the water to be cloudy and the nitrifying bacteria removes them the water will become clear, if this is true the nitrifying system (nitrifying bacteria) has a clear water function, but will it be?

　　    Anyone who has taken middle school chemistry knows that ammonia and nitrites are inorganic, and their presence does not change the clarity of the water, just as salt sprinkled into water does not make it muddy. Water never becomes cloudy with the presence of ammonia and nitrites, nor does it become clearer with the removal of ammonia and nitrites. Therefore, the nitrification system (nitrifying bacteria) has nothing to do with water clarity or turbidity.

        Why is the water in our fish tank cloudy? Biological turbidity is the main form of turbidity in aquarium water, which is manifested as chaotic and hazy water, in fact, this is a physical phenomenon, called"Tyndall effect (physics)"The bacteria is very small we can't see it with the naked eye. Bacteria is very small we can not see with the naked eye, but when it reproduces in large numbers, it will produce milky light, change the refractive index of water, so that the light is scattered, resulting in a decline in the clarity of water, we see that the water is cloudy is a result of bacteria reproduction to change the reflection of light caused by the results.

　　    Excessive organic matter, such as fish poop debris, can trigger a proliferation of heterotrophic bacteria, which can produce"Tyndall effect (physics)"Causes biological turbidity. There are two ways to control this biological turbidity:1and killing of overgrown heterotrophic bacteria.2, removing excess organic matter. So let's look at the functions that the nitrification system (nitrifying bacteria) has.

1Can a nitrification system (nitrobacter) kill bacteria?
　　    The answer is never.Nitrification system is used to cultivate nitrifying bacteria, nitrifying bacteria decompose toxins, toxins are metabolites of heterocysts, commonly known as heterocyst feces, nitrifying bacteria decompose heterocyst feces rather than heterocysts themselves, so they do not pose any threat to heterocysts and do not have bactericidal function. Some people may ask whether the nitrification system will be able to cultivate some bacteria that can kill bacteria in addition to nitrifying bacteria.?The answer is also no. There are some protozoa in nature that feed on bacteria such as phages, and many bacteria will secrete antibiotics and lysozyme to inhibit the growth of other bacteria, but they have nothing to do with the nitrification system, they don't need to attach to the biofilter media to grow and reproduce, and they don't need the water circulation system, and they are not cultivated by the nitrification system, so they don't have anything to do with the nitrification system.

2Can a nitrification system (nitrifying bacteria) remove organic matter?
　　    The answer is even less likely.Nitrifying bacteria can not decompose organic matter this is common sense, organic matter is the natural enemy of nitrifying bacteria, by organic matter encroachment of the filter media nitrifying bacteria can not grow and reproduce on it, so the organic matter can destroy the nitrifying bacteria so that it has no place to live, remove the organic matter is a heterogeneous bacterial work, the nitrifying bacteria can not do the work of this coarse work.