How long does it take to cycle an aquarium? The time it takes to complete the cycling process varies depending on the type of aquarium. For a freshwater aquarium, one month is likely to be enough, while in a marine aquarium, it takes between two and three months to stabilize all the parameters. How do you know if the cycling process has finished? In the first two or three days after introducing the water into the aquarium, you will notice that the water is cloudy due to the filtering effect and the various suspended matter that comes from the substrate. Later, the water begins to clear up until it is completely transparent. You might think that the process has finished and that you can start introducing fish... No! Throughout the process, you must periodically monitor the quality of the water, using the different tests available for this purpose. Once you manage to eliminate the ammonia and the nitrites drop to zero, you can say that the process has concluded and you can start introducing fish. The cycling process step by step The process for cycling the aquarium can be divided into three distinct phases: 1st Phase, appearance of the nitrifying bacteria In the first phase of cycling, the aerobic nitrifying bacteria Nitrosomonas appear, which are responsible for consuming ammonia and converting it into nitrite. For the Nitrosomas bacteria to make an appearance and prosper, we need the aquarium to contain Ammonia. We can get the aquarium to generate ammonia in three different ways: Adding fish food Fish food produces ammonia when it decomposes. You should add three to four flakes per day, for every hundred liters of aquarium. We will get the best results by breaking up the flakes, so that the decomposition is faster. We will continue with the process, until we manage to raise the level of nitrites present in the aquarium. Logically, this process has its advantages and disadvantages, such as the fact that the process is somewhat longer than if we use chemical products or that we have less control. However, not everything is bad. The great advantage is that we do not add chemicals to the aquarium, which are always debatable, and we add phosphates that are useful for the plants in the aquarium. What happens if I do not cycle the aquarium? If you do not cycle the aquarium and as soon as you buy your new aquarium you introduce fish, it is most likely that they will end up poisoned and die. In the best case, they can suffer all kinds of diseases and especially stress, due to being in an environment that does not have sufficient quality to survive. How to start cycling? The first thing we have to do to start cycling the aquarium is to start it. First of all, we will have to have decided what type of aquarium we would like to have, and then we will introduce the elements that will be part of it: substrate, decoration... everything except the fish, and in a first phase we will not introduce plants either. Of course, the aquarium filter must not be missing, very important for the cycling process to be correct and for the first bacteria to appear. You need to connect everything necessary to reproduce the chosen biotope: heaters and lights, although we won't turn these on until we put in the first plants. What is aquarium cycling? Cycling is a process by which we get colonies of bacteria to start settling in the aquarium, to help us with the nitrogen cycle. The bacteria that settle in the aquarium are part of the water filtration system. Thanks to their beneficial effects, part of the aquarium's own waste is degraded in a completely natural way, maintaining the natural balance of the ecosystem.