1、①Dirty water enters from the filter side; ②The water will first pass through the 3 layers of filter plates; ③Then water passes through the sponge filter box again; ④ Clean water enters the filter inside, ⑤Then by water pump flows out through front outlet or rotatable outlet tap. 2、Our Innovative water exchange design allows for quick and easy water changes. Rotate the outlet tap to change the water out of the tank by the included hose . 3、 But only part of the water can be replaced. fish tank filter meets the scientific fish farming, all the water will not be pumped away, allowing the fish to adapt. 4、 ①Pull out the outlet tap; ②Remove the top cover; ③Take out the small accessories; ④Install back cover and outlet tube; ⑤Install the fountain accessory head on the water change tube. After plugging in the power, aquarium filter will be an effect similar to a small fountain. The flow of water will also increase dissolved oxygen in the aquarium. 5、 This water change filter pump is the latest design. In addition to the powerful filtering function to bring you a clean and clear fish tank, its unique rotating outlet tap can meet your water change function needs, fish tank filter is multi-purpose. The additional small outlet tap plug create a small fountain effect in the fish tank, adding visual enjoyment while filtering.