understanding different aquarium filter types

Do You Know the Aquarium Filter Types?

In the vast realm of aquarium maintenance, an aquarium filter stands as a mighty guardian, safeguarding the delicate balance of aquatic life. With its intricate mechanisms, this filtration system expertly eliminates pollutants, purifying the waters and nurturing a thriving ecosystem.

From the humble internal filters nestled within the tank to the grandeur of external canister filters, the diverse array of aquarium filter types offers a plethora of options to suit every aquatic enthusiast's needs.

Embark on a journey of discovery as we explore the wonders of these filtration marvels.

Key Takeaways

  • There are three main filtration methods: biological, chemical, and mechanical.
  • Mechanical filtration helps to improve water clarity by removing visible debris.
  • Biological filtration is an essential part of the nitrogen cycle in aquariums.
  • There are two main types of aquarium filters: internal filters and outside filters.

Internal Filters

Internal filters are commonly used in aquariums to effectively remove pollutants and maintain water quality. These filters are located inside the tank and offer several advantages.

One advantage is their compact size, which makes them suitable for smaller aquariums or tanks with limited space. Additionally, internal filters are easy to install and maintain. They typically come with adjustable flow rates, allowing for customization based on the needs of the aquarium inhabitants.

Maintenance tips for internal filters include regular cleaning of the filter media to prevent clogging and ensure optimal filtration efficiency. It is also important to regularly check and replace any worn-out parts to maintain the filter's effectiveness.

Outside Filters

Both hang on back filters and canister filters are popular choices for aquarium owners who prefer outside filters.

Hang on back filters, also known as HOB filters, are easy to install and maintain. They hang on the back of the aquarium and use a pump to draw water into the filter, where it passes through different filter media to remove impurities.

Canister filters, on the other hand, are larger and provide excellent filtration capabilities. They are usually placed under the aquarium and have multiple compartments for different types of filter media.

The advantages of outside filters include their ability to provide efficient mechanical, biological, and chemical filtration, their larger capacity for filter media, and their ability to maintain water clarity.

To ensure proper maintenance of outside filters, it is important to regularly clean or replace the filter media, check the impeller for any debris, and monitor the water flow rate.

Sponge Filters

Sponge filters, along with their unique design and functionality, offer a reliable and efficient method of biological and mechanical filtration in aquariums. These filters consist of a sponge-like material that traps solid particles and provides a surface for beneficial bacteria to grow.

Here are some advantages of using sponge filters:

  • Sponge filters are cost-effective compared to other types of filters.
  • They provide excellent biological filtration by promoting the growth of beneficial bacteria.
  • Sponge filters are gentle on delicate or small fish, as they do not create strong water currents.
  • They are easy to clean and maintain, requiring only periodic rinsing of the sponge.

However, there are also some disadvantages to using sponge filters:

  • Sponge filters may not be suitable for large aquariums or tanks with heavy waste loads.
  • They have limited mechanical filtration capability and may not effectively remove fine particles.
  • Sponge filters can be bulky and take up space in the aquarium.

When choosing a sponge filter for your aquarium, consider factors such as the tank size, fish species, and waste production. Ensure that the filter is appropriately sized to handle the waste load and provides sufficient surface area for bacterial colonization.

Under Gravel Filters

An often overlooked but effective option for aquarium filtration is the implementation of under gravel filters, which enhance the biological and mechanical filtration processes in the tank. Under gravel filters consist of a plate or grid that is placed at the bottom of the aquarium, with layers of gravel or substrate covering it. Water is drawn through the gravel by an air pump or powerhead, which promotes the growth of beneficial bacteria and traps solid waste particles.

One of the main advantages of under gravel filters is their cost-effectiveness, as they are relatively inexpensive compared to other types of filters. They also provide a large surface area for beneficial bacteria to colonize, leading to improved biological filtration. However, under gravel filters have some drawbacks. They can be more difficult to clean compared to other filters, as the gravel needs to be periodically vacuumed to remove accumulated debris. Additionally, under gravel filters may not be suitable for aquariums with certain types of fish or plants that require a specific substrate.

To maintain under gravel filters effectively, regular maintenance is crucial. It is recommended to vacuum the gravel regularly to prevent the buildup of waste and to ensure proper water flow. The frequency of vacuuming will depend on the size of the tank and the number of fish. It is also important to monitor the water parameters regularly to ensure that the filter is functioning properly. If the water becomes cloudy or the fish show signs of stress, it may indicate a problem with the filter that should be addressed promptly.

Box Filters/Corner Filters

Within the category of internal filters, box filters, also known as corner filters, are a popular choice for aquarium enthusiasts. These filters offer several advantages and disadvantages for aquarium owners.

Advantages of box filters/corner filters include:

  • Easy installation and maintenance: Box filters can be easily installed in a corner of the aquarium, making them convenient for aquarium owners. They are also easy to clean and maintain, requiring minimal effort.
  • Effective biological filtration: Box filters provide a large surface area for beneficial bacteria to colonize, allowing for efficient biological filtration. This helps in breaking down harmful components and maintaining water quality.

Different types of filter media used in box filters/corner filters include:

  • Sponge media: Box filters often contain sponge media, which acts as mechanical and biological filter media. The porous structure of the sponge traps debris and provides a surface for beneficial bacteria to grow.
  • Activated carbon: Some box filters have compartments for activated carbon, which helps in chemical filtration by adsorbing impurities and odors from the water.

Despite their advantages, box filters/corner filters have a few disadvantages:

  • Limited mechanical filtration: Box filters may not provide as effective mechanical filtration compared to other types of filters. They may not be able to trap smaller particles efficiently.
  • Limited flow rate: The flow rate of water through a box filter is relatively low, which may not be suitable for larger aquariums or those with high bio-load.

Hang on Back Filters and Canister Filters

Both hang on back filters and canister filters are popular choices for aquarium enthusiasts due to their effectiveness and versatility in maintaining water quality.

Hang on back filters, as the name suggests, are attached to the back of the aquarium. They are relatively easy to install and maintain, making them suitable for beginners. Hang on back filters provide mechanical and chemical filtration, trapping solid particles and removing impurities through activated carbon or other filter media.

On the other hand, canister filters are external filters that are placed outside the aquarium. They offer a larger filtration capacity and can accommodate a variety of filter media, including biological media for efficient biological filtration. Canister filters are effective in maintaining water clarity and are often preferred for larger aquariums or tanks with high bio-load. However, they require more maintenance and can be more expensive compared to hang on back filters.

In terms of filtration effectiveness, canister filters generally provide superior filtration due to their larger capacity and the ability to accommodate a variety of filter media. However, hang on back filters are still effective in maintaining water quality, especially for smaller aquariums with moderate bio-load.

Frequently Asked Questions

How Often Should I Clean or Replace the Filter Media in an Internal Filter?

The cleaning frequency and filter media replacement for an internal filter depend on various factors such as tank size, stocking levels, and filter type. It is recommended to clean or replace the filter media regularly to maintain optimal filtration efficiency and water quality.

Can Under Gravel Filters Be Used in Saltwater Aquariums?

Under gravel filters can be used in saltwater aquariums, but they have pros and cons. They provide biological filtration but may cause substrate compaction. Other filter types, like hang on back and canister filters, offer alternative options with their own advantages and disadvantages.

What Are the Benefits of Using a Box Filter or Corner Filter in an Aquarium?

Box filters and corner filters offer several benefits in aquariums. They provide effective mechanical and biological filtration, improving water clarity and maintaining a healthy environment for fish. They are also cost-effective, easy to install, and require minimal maintenance.

How Do Hang on Back Filters Differ From Canister Filters in Terms of Installation and Maintenance?

Hang on back filters are easier to install and maintain compared to canister filters. They are also more affordable. However, canister filters offer superior filtration capacity and are suitable for larger aquariums.

Are Sponge Filters Suitable for Large Aquariums or Only Smaller Tanks?

Sponge filters are suitable for both large aquariums and smaller tanks. They have a long lifespan and provide several benefits in planted tanks, such as mechanical and biological filtration, gentle water flow, and a large surface area for beneficial bacteria to thrive.


In conclusion, understanding the different types of aquarium filters is vital for maintaining a thriving aquatic ecosystem.

The presence of pollutants in the water can be detrimental to the well-being of fish and other aquatic organisms.

By utilizing mechanical, biological, and chemical filtration methods, aquarium filters effectively remove waste and harmful components, ensuring a clean and healthy environment.

Whether using internal filters or outside filters, each type has its own advantages and disadvantages, emphasizing the importance of choosing the most suitable option for your aquatic setup.



Meet me, your dedicated author and fish aficionado. With a deep-rooted passion for all things aquatic, I bring a wealth of knowledge, experience, and enthusiasm to this fish and aquarium website. As an avid fishkeeper myself, I understand the joys and challenges that come with creating a thriving underwater world. Through my articles, guides, and recommendations, I strive to provide you with accurate, reliable, and engaging content that will enhance your fishkeeping journey. Join me as we dive into the fascinating realm of fish and aquariums, and together, let's make your aquatic dreams a reality.

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