When beginners set up a new aquarium, the water may appear yellow or white. There is no need to rush to change the water, as sometimes this does not solve the problem. There are four main reasons for the whitening of aquarium water, which everyone can check against their own situation.
Inadequate Filtration
Some filters merely circulate water without actually filtering it. These filters are filled with biological cotton, which is ineffective at filtering out small particle impurities and lacks adsorption capabilities. Moreover, the quantity of filter cotton is often insufficient, and there is a lack of other filter media, relying solely on the cotton. The establishment of a nitrification system is very slow, and over time, the water can appear white.

Overstocking Fish
Beginners must control their purchase quantity when starting to keep fish. Today, a fan asked me to recommend a type of fish, and I suggested the Black-tailed Arowana, but he said he wanted a hundred at once. Friends, fish keeping should be gradual, and it is recommended to buy ten at a time. This way, even if some fish die, it will be one by one. If you buy a hundred at once and manage them improperly, you might end up with a mass die-off, and then it would be too late to cry. Additionally, too many fish can easily lead to water quality deterioration, causing many problems.
Overfeeding
Fish keepers, especially beginners, often want to observe their fish eating and thus overfeed them, hoping for rapid growth. However, this only leads to more eating and more waste, with uneaten food residues making the water turbid, and in severe cases, it can even lead to fish death.
Issues with Substrate Materials
The fourth factor is the material laid at the bottom of the aquarium, such as volcanic stone and stream stone, which are difficult to clean thoroughly. Therefore, once water is added to the tank, the water will remain turbid. To quickly clarify the water, a strong filtration system is needed. If the filtration is not effective, there will be a large amount of fine particulate impurities at the bottom, and it will take a long time for the water to settle and become clear.

Summary and Recommendations
If beginners want clear water and healthy fish in their aquariums, it is essential to choose a filtration system suitable for their own aquarium. When setting up a new tank, it is advised to buy fewer fish and feed them less. In this way, during the beginner stage, your aquarium can basically achieve satisfactory results, with clean water quality and healthy fish survival.
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