Natural aquarium soils (quartz, gravel, etc.) look as natural as possible and quite inexpensive in cost when buying. But they need regular cleaning, especially if you keep bottom fish, such as catfish or loach fish, which spend most of their life in close contact with the substrate.
The nitrogen cycle is an integral part of the existence of any aquarium. The nitrogen cycle refers to the cycle of ammonia, nitrites, and nitrates. Plants, aquarium inhabitants, and bacteria, i.e. all components of an aquarium biosystem. If you want to know why your aquarium gets cloudy, keep reading.