▷ Hamburg mat filter | All information about installation and operation

Filter mats from the pet shop are usually colored blue. As a rule, the mats are 5 or 10 centimeters thick. There are fine and coarse pore size mats.

Fine mats clog faster under high loads than coarse mats. Mechanical filtration is initially faster with fine mats than with coarse mats. The fine filter performance may be better with fine mats because the inner surface is larger. When moving or changing the water, the valuable filter sludge falls out of the coarse mats more quickly. However, the higher sludge content can be advantageous with coarse mats because it is colonized by bacteria.

Fine mats should be preferred in normal aquariums and with normal residents. Coarse mats should be used when residents are digging or digging heavily in the soil.

If the mats have been in service for a period of time, both mat types are likely to be equivalent.

Filter mats can easily be cut with an electric kitchen knife. Thanks to the long double blade, you can get straight cutting surfaces even with 10 cm thick foam.

Normal, long kitchen knives with a blade that is 20 to 30 centimeters long are also suitable. The knife is freshly ground and not deburred. Don’t try to cut all the way through with one cut. If you cut along a ruler several times, the cut will be clean.

If the cut is to be particularly straight, a ruler or a metal rail is placed on both sides of the filter mat and cut along these rails.

Other suitable knives are carving knives, butcher knives, cutters, etc.

Another option is to let the mat soak up water and freeze it. After that, the mat can be cut with a jigsaw.

Using scissors will squeeze the mats too much, causing the cut to become wavy.

To make a hole e.g. B. for pipes in a mat, the easiest way is to make a short cut in the mat with a normal, sharp cutter knife. It is often sufficient to poke the knife briefly through the mat. A small cut also closes up well if the cut was in the wrong place. A new cut can then be made at a different point.
The cut should be slightly shorter than the diameter of the pipe so that the mat fits snugly against the pipe. For larger pipes, the cut is made a little wider or two cuts are made crosswise.

A hole cannot simply be drilled in a filter mat. In any case, a lot of material is torn out of the mat and the hole becomes very irregular. There is a risk that the drill will seize up and the mat will wrap around the drill. This can result in injury to the fingers.

For drilling, the mat must be placed between two boards. The boards are firmly pressed together with screw clamps. When the mat is pressed in place, a hole can be drilled through the boards and mat.

Alternatively, the mat is soaked in water and then frozen. The block of ice can be pierced with a sharp drill.

A plastic pipe is ground at an angle with a small angle grinder fitted with a grinding attachment, just as the stems of cut flowers are cut off. Inexpensive installation pipes and bends for cable ducts are suitable as pipes. The edges become very sharp. The sharp edge of the tube is drilled into the mat with rotating movements. So that the hole does not run, you must not press too hard on the mat. The tube fits so snugly in the hole. Finally, the pipe is deburred so that nobody cuts themselves later.

A 1 mm steel wire is bent 2 x 90° so that a U is formed. Two small strips of wood of approx. 10 x 3 mm are screwed over it on both sides so that the two ends of the wire protrude approx. 10 mm. A voltage of approx. 12 volts / 2 – 3 A is applied to the wire ends. The wire ends are drilled into the mat and the device is rotated once by 180°.

A completely different way of laying pipes is to run the pipes over the mat. To do this, a groove is cut into the upper edge of the mat. The pipe is laid in the gutter. At the same time, the channel determines the maximum water level and serves as a safety overflow if the mat becomes dense and water accumulates in front of the mat.

Filter mats can be connected to each other with fishing line. 30 or 35 fishing line does not cut into the mats as much. This method is particularly useful when the mats need to be connected underwater in an aquarium that is already running.

A slit can be cut in opposite places in both mats. A plastic rail is pushed into the slots, which holds the mat together.

In addition, the mats can be glued together with aquarium silicone. Bonding with silicone is usually sufficient. The adhesive surface is of course omitted for filtering.

A rubber-based agent similar to silicone is Adheseal (Article No. 423) from Innotec. It reacts under water with the oxygen contained in the water. Fish are not harmed.

Cotton threads, etc. are not suitable because they are quickly decomposed by the bacteria in the water.

Rigid PVC is non-toxic, but can only be glued with special adhesives. Like almost all plastics, rigid PVC cannot be glued with silicone.

Acrylic glass can be glued with acrylic glue.

Polystyrene is a material that B. the toy models are produced. Appropriate glue is available in toy shops.

Normal silicone is not suitable to be glued under water. Because moisture is necessary for setting, silicone sets better under water than outside of water, but because of the moisture on the materials to be connected, e.g. B. glass, silicone does not stick to the respective material.

Silicone only sticks to dry surfaces. Fingers or other tools are moistened so that the moist silicone does not stick to the finger when smoothing out the glued seams. For better adhesion and better wetting, add a little washing-up liquid to the water to moisten it.

If uncured silicone comes into contact with water, a skin forms very quickly, which means that the silicone can no longer bond properly to the glass. This skin forms much faster in water than in air.

Special underwater silicone is more suitable.