If you have a small or medium-sized Aqua One fish tank, an internal filter is sufficient, cheaper, and more practical. The product offers more freedom when placing the aquarium in the home, which is much quieter. The internal filter with a sponge is the simplest version available: its great advantage is that it allows the development of the biological remains taken over by the respective sponge, which any aquarium needs to maintain a healthy environment for fish. Its disadvantage is that the respective sponge is covered with a slime that no longer allows efficient filtering, so it must be cleaned.
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