The external filter is installed directly above the surface of the water or even outside the aquarium. There are several types of such equipment. When choosing a filter must take into account the size of the aquarium.
Varieties of devices
External filters are:
- mechanical, biological and chemical;
- suspended and canister.
Mechanical models as a cleaning filter element have a special fiber or sponge. If the filter element is dirty, cleaning will be inefficient. Therefore, the owner must regularly check the equipment.
Biological filters are filled with porous material that eliminates hazardous elements (for example, ammonia). In such devices, it is not the filler itself that is important, but the colonies of nitrifying bacteria that live in it. Such filtering systems are very effective and contribute to the complete purification of an artificial reservoir.
Chemical models perfectly purify the environment from phosphates and nitrates. The filter element here can serve as a special resin or activated carbon.
Advantages of external systems
Classic external filters are canister, but outboard ones have practically the same advantages. External filters:
- much more internal, they perfectly clean even large aquariums;
- do not occupy space inside the aquarium;
- inside such devices there is much more cleaning material;
- versatile and may have several different fillers at once.
To assess the effectiveness of the equipment, just look at its size and filler. High-quality devices are quite quiet and do not require constant maintenance.
How the system works
From the filter to the aquarium are drain and suction hoses. On the intake hoses, water is collected by an electropump into the filter canister, and then passes through filtering materials. The cleaned fluid returns to the aquarium through the drain pipes. Water is also drained by a pump.
On the external system, you can additionally put an aerator that will deliver air to the colonies of nitrifying bacteria. This will contribute to their enhanced reproduction. The more bacteria, the higher the quality of cleaning fluid.
In suspension filters the construction is divided into several sections. In each section there is a cleansing filler. Different types of filler are used: chemical, mechanical and biological. The options for supplying and draining water here can be different – it all depends on the design features of a particular model.
What aquarium is suitable for
If the aquarium is small, then you can use a regular submersible filter. Exterior models are ideal for large aquariums. In such systems, a lot of fish, water is constantly polluted. Large amounts of water are extremely difficult to clean with a conventional submersible filter.
How to understand that you need an external filter? Experts believe that if the volume of the aquarium is more than 200 liters, then it’s time to think about buying more serious equipment. Small submersible systems will not be enough for such an environment.
Information for the article provided by the company "Nemo"