Matten Filter – The Ultimate Guide To Low-Maintenance, High-Efficiency

Do you ever feel like you are spending more time cleaning your aquarium filter than actually enjoying your fish? Keeping water parameters stable and crystal clear can often feel like a full-time job, especially in smaller tanks or high-bioload breeding setups.

The good news is that there is a decades-old secret used by expert German breeders that can practically run itself for years. This system, known as the matten filter, offers a level of biological stability that most modern “plug-and-play” filters simply cannot match.

In this comprehensive guide, we are going to dive deep into the mechanics of the Hamburg Mattenfilter (HMF). You will learn how to set one up, why the specific foam density matters, and how this simple sheet of sponge can transform your hobby into a low-maintenance success story.

What is a Matten Filter and Why is it a Game-Changer?

At its core, a matten filter is a large sheet of reticulated foam placed vertically at one end of your aquarium. Unlike a standard sponge filter that sits in the middle of the tank, this system creates a complete wall that partitions a small section of the aquarium.

The magic happens when you place a water return system—usually an airlift tube or a small powerhead—behind that foam wall. Water is pulled through the entire surface area of the sponge and pumped back into the main tank area.

This creates a massive “bio-reactor” where the entire sheet of foam becomes a colony for beneficial nitrifying bacteria. Because the surface area is so vast, the flow rate per square inch is incredibly slow, which is exactly what these bacteria need to thrive.

The History of the Hamburg Mattenfilter

Originating in Hamburg, Germany, this design was born out of a need for reliability and efficiency in large-scale fish rooms. Breeders needed a way to filter hundreds of tanks without the risk of mechanical failure or frequent clogging.

They discovered that by using a simple sheet of foam and the power of rising air bubbles, they could create a filter that lasted for years without being touched. It is a testament to the “less is more” philosophy in the aquarium hobby.

The Science of Biological Surface Area

When we talk about filtration, most people think about mechanical filtration—trapping fish poop and debris. While that is important, the real heavy lifting in any tank is done by biological filtration.

The matten filter excels here because it provides an enormous amount of real estate for bacteria. In a standard hang-on-back (HOB) filter, the water rushes through a tiny cartridge at high speeds, often bypassing the bacteria entirely.

In an HMF setup, the water moves at a “creeping” pace. This slow movement allows the bacteria more time to process ammonia and nitrites. It also allows for the development of diverse micro-fauna that help break down organic waste before it even reaches the pump.

Understanding PPI (Pores Per Inch)

Not all foam is created equal, and choosing the right density is critical for your success. Reticulated foam is measured in PPI (Pores Per Inch), and each level serves a different purpose in your aquarium.

• 10-20 PPI: Coarse foam. Great for large fish like cichlids or goldish where you need higher flow and less risk of clogging from large waste particles.
• 30 PPI: The “sweet spot” for most hobbyists. It is fine enough to prevent baby shrimp from getting sucked through, but coarse enough to maintain flow for a long time.
• 45 PPI: Very fine foam. This provides the most surface area but can clog faster if you have a high bio-load. It is perfect for shrimp-only tanks or fry rearing.

Step-by-Step Guide to Setting Up Your First HMF

Setting up this system is surprisingly easy and very budget-friendly. You don’t need expensive proprietary equipment—just a few basic materials and a bit of “DIY” spirit. Don’t worry—this setup is perfect for beginners!

1. Measure and Cut Your Foam

First, you need to measure the internal width and height of your aquarium. You want to cut your Poret foam or aquarium-safe sponge about 1/4 to 1/2 inch wider than the tank itself. This ensures a “friction fit” so that the foam stays in place without glue.

Use a sharp utility knife or an electric bread knife to get a clean, straight edge. Safety tip: Always cut away from your body and take your time to ensure the foam sits flush against the glass walls.

2. Create the “Behind the Scenes” Space

Slide the foam into the tank, usually about 2-3 inches away from the side wall. This creates a void space behind the sponge. This area is where your heater, air stones, or pump will live, keeping them hidden from view.

If you find the foam is bowing too much, you can use small glass or plastic strips (rails) glued to the side of the tank with aquarium-safe silicone to hold the foam in place. However, for most small tanks, the tension of the foam is enough.

3. Installing the Airlift or Pump

Now, you need a way to move water. The traditional method uses an airlift tube. This is a PVC or plastic pipe with an air stone at the bottom. As the bubbles rise, they pull water up the tube and over the foam wall.

If you prefer more flow or have a larger tank, you can use a small submersible powerhead. Simply attach a piece of flexible tubing to the output of the pump and poke it through the foam so it discharges into the main tank area.

Choosing the Right Power Source: Air vs. Water Pump

One of the most common questions we get at Aquifarm is whether to use an air pump or a powerhead for a matten filter. Both have their place, depending on your specific goals.

The Benefits of Air-Driven Systems

Air-driven systems are the gold standard for shrimp and fry tanks. Because there are no spinning impellers, there is zero risk of sucking up tiny inhabitants. They also provide excellent gas exchange by agitating the water surface.

Furthermore, air pumps are incredibly efficient. You can run dozens of tanks off a single large linear piston air pump, which is why you see this setup in almost every professional breeding facility.

The Case for Powerheads

If you are keeping larger fish or plants that require specific flow patterns, a powerhead might be better. Powerheads are nearly silent compared to the humming and bubbling of an air system. They also allow you to direct the flow more precisely to avoid “dead spots” in the aquarium.

Why Shrimp Keepers and Breeders Swear by This Filter

If you are into Neocaridina or Caridina shrimp, the matten filter is arguably the best filtration system you can choose. Shrimp are constant grazers, and the large surface of the foam becomes a 24/7 buffet for them.

The foam develops a thick layer of biofilm and microorganisms. You will often see your shrimp spending their entire day on the “wall,” picking off microscopic food particles. This leads to higher survival rates for shrimplets and healthier adults.

For fish breeders, the safety factor is unmatched. Fry are delicate and can easily be killed by the intake of a standard filter. With this system, the suction is spread across such a large area that even the weakest newborn fish can swim right up to the sponge without danger.

Maintenance Myths: How Often Do You Really Need to Clean It?

One of the biggest advantages of this system is the lack of maintenance. Many hobbyists are shocked to learn that a well-installed HMF can go 12 to 24 months without a single cleaning. But how is that possible?

In a traditional filter, the small sponge gets clogged with “gunk” quickly. In a matten filter, that “gunk” is actually a living ecosystem. Detritus-eating worms and bacteria live inside the foam, breaking down waste into basic elements that your plants can then absorb.

When and How to Clean

You only need to clean the foam when you notice a significant “drop” in the water level behind the sponge compared to the front. This indicates that the pore structure is finally becoming restricted.

To clean it, simply use a gravel vacuum to suck debris off the surface of the foam during your regular water change. Never take the foam out and wash it under tap water! Doing so will kill the massive colony of beneficial bacteria you have worked so hard to grow.

If the foam is truly clogged, you can remove it and gently squeeze it in a bucket of dechlorinated tank water. You want to remove the excess sludge while keeping the “good” bacteria intact within the sponge’s core.

Troubleshooting Common Issues

Even though this system is simple, beginners can sometimes run into a few hiccups. Let’s look at how to solve the most common matten filter problems.

1. The “Bowing” Foam

If your foam sheet starts to bend or bow into the void space, it means the water pressure is higher on the tank side. This usually happens if the foam is too thin or if it is starting to clog. Using 2-inch thick foam is generally the best way to prevent this.

2. Tannin and Debris Buildup

Because the foam is a massive mechanical trap, it can sometimes trap fine particles that make the water look a bit yellow. If you want “polished” water, you can tuck a small bag of activated carbon or chemical media behind the foam in the void space.

3. Low Flow from the Airlift

If your airlift tube isn’t moving much water, check your air stone. Over time, calcium deposits can clog the tiny holes in the stone. Simply replacing the air stone or soaking it in vinegar for an hour usually restores the flow immediately.

Frequently Asked Questions (FAQ)

Can I use a matten filter in a planted tank?

Absolutely! In fact, they are great for planted tanks because they provide a stable environment for nutrient cycling. Just be aware that if you use high-pressure CO2, the surface agitation from an airlift might gass off some of your CO2. In this case, use a powerhead instead.

Is it ugly? How do I hide the giant sponge?

While a big blue or black sponge might not be everyone’s aesthetic, it is easy to hide. You can plant Java Moss, Anubias, or Java Ferns directly into the foam. Over time, the plants will grow across the surface, creating a beautiful “living wall” that hides the filter completely.

How long does the foam last?

High-quality reticulated polyether foam (like Poret foam) is designed to last for 10 years or more. It does not break down or crumble like the cheap sponges often found in budget filters. It is a long-term investment in your aquarium’s health.

What size tank is best for this?

This system works for any size, from a 2.5-gallon nano tank to a 100-gallon display. However, it is most popular in 10 to 40-gallon tanks where maximizing internal space and biological stability is a priority.

Conclusion

The matten filter is a perfect example of how the simplest solutions are often the best. By mimicking the natural filtration processes found in nature, you create a stable, healthy, and low-maintenance environment for your aquatic pets.

Whether you are a shrimp enthusiast looking to protect your shrimplets or a busy hobbyist who wants to spend less time on chores, the Hamburg Mattenfilter is a proven choice. It might not be the newest “high-tech” gadget on the market, but its reliability and biological power are second to none.

Give it a try in your next tank setup. You might just find that you’ll never go back to “standard” filters again! If you have any questions about choosing the right PPI or sizing your pump, feel free to reach out to us here at Aquifarm. Happy fish keeping!