Poret foam filters is some of the best filtration money can buy. They are very simple and easy to use. 1 Poret filter for a 10 gallon aquarium has over 20 Times the surface area of a sponge filter for a 125 gallon aquarium! Real Talk! You only need a small air pump to run it. This special foam has a patent on it and can only be bought from Swiss Tropicals. That have great customer service any many different filter options. This is one I was setting up this morning. I put my heater behind the foam for a super clean look! The foam is cut slightly wider than the tank so you can bow it in one end of the tank. The foam can be bought from 2 inches thick up to 5 inches thick.