Review on 🐠 Aquapapa Corner Filter: Efficient Air-Driven Bio Sponge Ceramic for Nano Fish Tank Aquarium (Ship from CA USA) by Angel Young

Not exactly a sponge filter, this item is made as cheaply as possible. However, it is a worthy alternative to mini canisters, which can be customized with spacers and granular media. It's filled with gravel, not bio rings as shown in the picture, so I'd recommend purchasing alternative filling instead of the cheap gravel that it comes with. Disappointed because I had to buy another medium but it works fine now. It is also not recommended to use a tank larger than 10 gallons, rather than 15 as specified by the manufacturer. A good alternative to the mini canister for the small purse, but not for everyone.