Internal Fish Tank Filters In Search Of The Best

Internal Fish Tank Filters In Search Of The Best

Going to buy a filter for cleaning aquarium water, you need to imagine which device is more suitable in each specific case: external or internal, with high capacity or low, expensive or cheap. A large number of aquarists stop in their choice on internal cleaners. There are a lot of models of such filters, and often the question arises, which of them should be chosen.

Internal water filters are very popular in the aquarists society. They have:

  • small dimensions;
  • installed directly in the tank;
  • quite easy to operate and maintain.

Device and principle of operation

Internal cleaners have a fairly simple device. Each of them is a cylindrical housing with slots for drawing in water, to which a small pump is attached.

Inside the case is one or more filter materials. In the simplest form, this material is foam rubber (flexible polyurethane foam).

In addition to the closed filters, there are open-type pumps that lack a solid body and the sponge is located directly in contact with the aquarium.

Water, passing under pressure through the foam cells, gets rid of mechanical impurities and goes back to the aquarium. Colonies of saprophytes (microorganisms accumulating in foam rubber cells) produce biological water purification, turning decomposed organic residues into inorganic substances.

In appearance, the device looks like a glass. That is what the owners of ornamental fish often call it.

Internal Fish Tank Filters In Search Of The Best

Closed filter with foam filling.

Types of aquarium internal filters

Devices can be divided by filtering capabilities. The simplest glasses carry out only mechanical water purification and partially biological. Accordingly, they are the cheapest.

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In some models, the number of sections for the installation of filter material is increased, which also allows for chemical treatment of water using activated carbon or zeolite.

Internal filters also differ in their performance, that is, in the volume of water that is pumped through the system per unit of time. Immediately it should be noted that the 300-liter capacity is the principal limit for the technical devices under consideration.

There are modern devices that have additional options, for example:

  • built-in water heater to maintain the temperature in the aquarium;
  • an injector for supplying air with water;
  • regulator and pump power indicator;
  • flow direction switch and others.

Of course, accessories and options affect the price of the device.

Internal Fish Tank Filters In Search Of The Best

Pump with ceramic filler.

Which filter is better?

Perhaps no one aquarist can give a clear answer to this question. There are quite a few models on the market that have been successfully operated for a long period.

If we consider the problem from the point of view of the price for the device, then among the domestic cleaners of economy class it is possible to distinguish products of the German company Sera.

Cheap devices of this brand L30, L60, L120, L150 and even L300 are easy to use and reliable. The numbers indicate the volume of the aquarium for which they are intended.


Italian devices of the Fluval brand are long-lived in the market of aquarium accessories. The best-selling device in the Italian model range is the Fluval4 Plus. He has a strong pump, power flow indicator and a modern, memorable design.

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However, this model has relatively large dimensions, and its filter elements quickly become clogged. According to the declared design features, the filter cartridge can be changed without stopping the operation of the device and without removing it from the water.

But in fact, in the course of this operation, some of the garbage goes back into the water anyway. It is better to turn off the device for a while and quietly change the cartridge.

AquaEl FAN

Domestic AquaEl FAN Polish aquarium cleaners have become very popular. And completely justified. Having low power consumption with a relatively powerful pump, Polish devices are reliable, simple, effective.

They compare favorably with their Chinese and some European counterparts with an original filtering material (a phenol-free sponge) on which bacteria actively settle, providing high-quality processing of organic residues and nitrogen compounds.

Internal Fish Tank Filters In Search Of The Best

Filter Aquael Fan.


The internal filtering devices of the Eheim brand can be called the elite of this type of devices. Designers of the German company Eheim GmbH Co meticulously and with fiction approached the problem of creating a unified filter.

For example, the model Eheim 2212 AquaBall has the original device of the outlet. Like a joystick, it can be rotated to either side with a ball design. This is very convenient, since the flow of water and air bubbles can even be directed downwards.

The considered devices, which are the most expensive in their class, have only one drawback – the axis of the pump impeller is ceramic (in all other models it is metal). Therefore, special care must be taken when disassembling and maintaining such a filter.

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The variety of water filters inside the aquarium is large. Which one is better? Perhaps one that satisfies the requirements of reliability, functionality, efficiency and is suitable for an aquarium of a particular tank.