• Basic Principles of the Hamburger Mattenfilter (HMF)

    In this article I will cover the basic principles of how to use a Hamburger Mattenfilter (HMF). HMF filters are essentially a form of sponge filter that utilizes a piece of foam as the filter material. One of the most popular foams used is made by Poret®. Two forms of filtration are achieved from using HMF filters: mechanical and biological, as explained in Basics of Filtration and Types of Filters.



    Poret® foam comes in pore sizes ranging from 10-45 PPI (pores per inch). 30 PPI is ideal for shrimp as the pore size is small enough to prevent shrimplets from going through. It also comes in a variety of colors.


    Closeup of 30 PPI Poret® foam.

    The foam is generally placed in one corner of the tank or used to cover a whole side or back of the tank. The foam itself is not a filter; you need a way to displace the water behind the foam back into the main area of the tank, creating the filtration mechanism. To do this, you can use either a powerhead or an air-driven system. A cut is made near the top of the foam to place the powerhead outflow or airlift tube.




    PVC piping can be used to make an airlift tube. A small hole is drilled at the bottom of the tube to insert the airline.






    Other equipment, such as heaters, can be placed behind the foam and out of view in the main area of the tank.

    As air passes through the tube, it displaces the water from behind the foam back into the main area of the tank, at the same time causing water from the main tank to go back through the foam, thus resulting in the filtration mechanism.




    OE Black Tiger on Poret® foam.

    HMF filters are a cost effective method of filtration. The large and porous surface area is ideal for beneficial bacteria to colonize, supporting the biological filtration. It is also shrimp safe and requires very little maintenance.