Many new fish tanks have in-built filters, but this isn’t always the case, making it important to get the appropriate model for your home aquarium. This device performs a vital task––but the ...

As a rule of thumb, a 20-gallon fish tank should have a filter that flows between 100 to 200 gallons an hour (GPH).

You'll need a cheap filter—the cheaper the better, the fancy features like Bio-Wheels and specialized media found in premium filters will be wasted on this project—and a large bowl.