This is a sponge filter marketed by Swiss Tropicals called the Hamburg Matten filter (HMF). The simplest version is called the "Mattenfilter" by Swiss Tropicals and is simply an an air lift tube with a piece of thick urethane foam designed to go across the entire width of the aquarium. This "across the tank" option is very unattractive and I do NOT recommend it simply because of aesthetics.
I can recommend the Swiss Tropical “Cornerfilter”. These use two siliconed in place brackets to hold a piece of urethane foam in a radius in the corner of the aquarium. Swiss Tropicals supplies an air lift tube with each kit. I recommend throwing out the air lift tube and placing a pump behind the foam to pump the water over the foam and back to the aquarium, as is shown above.
These “Cornerfilters” have the following obvious problems:
- They are only slightly less ugly and obtrusive than a sponge filter.
- It is virtually impossible to clean the mechanical filter bad gunk without also cleaning out the beneficial biofilter good gunk.
- It is really difficult to get the foam out of the aquarium without really messing up the aquarium.
- It takes up a lot of space in the aquarium
But note that this filter CAN be done in such a way as to give very good filtration and crystal clear water. It is a good cheap option for smaller aquariums. One has to add a pump which pumps the water OUT of the Matten filter into the aquarium. Point the outlet of the pump up at the surface of the water at about 30 degrees to optimize the amount of “choppy waves”. Size the pump to put at least 2X turnover through the foam.
Then simply don’t clean the filter until the foam starts pushing in (i.e. do not do any mechanical filtration). Only use the 20 ppi foam, not the 30 ppi foam. This can give very clear water as the foam used with this is a very good media. Note that air lifts won’t give enough flow to do a good job.
Swiss Tropicals has made some improvements in regard to aesthetics. Black foam is available now, which is much less of an eyesore than the blue, and the white plastic rails that hold the Poret foam in the image above have been replaced with clear rails.
A tip for maintenance: one can cut the foam above the substrate line before installation. The above-ground portion can be taken out and serviced if necessary, and the lower portion stays behind to prevent the substrate from shifting.
And one can buy foam over the internet quite cheaply and get clear plastic “L” sections (used to protect the corners of plaster walls) from your hardware store. Cut the “L” sections to size, glue in place, and one has a DIY version of the “Cornerfilter” which is much cheaper than the Swiss Tropicals version. There are several YouTube videos on how to do this.
There is an American made variation on this filter, the Aquatica “hydrodynamic filtration” filter. It is basically just a precision cut piece of foam which goes completely across the width of the aquarium. There are one or two air lift tubes which provide the flow. This filter doesn’t use brackets but obviously at the front to your aquarium there will be part of the aquarium visible as blocked off with foam. This is just not an attractive option for a decorative aquarium. It might be useful for a breeding or quarantine aquarium.
Bottom of the Tank Matten Filter
Another interesting type of Matten filter is placing a piece of charcoal colored foam across the bottom of the aquarium over under gravel filter plates. We discuss this in this article: