All You Need to Know About Aquarium Filters: Types and Tips

Everything you need to know about aquarium filters: types, filter media, and tips

A good filter is essential for a healthy and clear aquarium. It removes waste and ensures a stable ecosystem.

But which type of filter and filter media should you choose? Below, we discuss the different types of aquarium filters, filtration methods, and provide practical tips to help you make the best decision for your situation.

Types of Aquarium Filters

1. Internal Filter
   An internal filter is located inside the aquarium and is suitable for small to medium-sized aquariums. It is compact and easy to install but takes up space inside the aquarium. It usually combines mechanical and biological filtration.

   Tip: Clean the filter media with aquarium water, not tap water, to preserve beneficial bacteria.

2. External Filter
   This type of filter is placed outside the aquarium and offers more space for filter media, making it suitable for larger aquariums. It is more powerful than an internal filter and provides better water circulation.

   Tip: Maintain external filters well by regularly cleaning the hoses and replacing chemical filter media on time. 

3. Sump Filter
   A sump filter is a highly effective filter for larger aquariums. It uses a separate tank where water flows through various filter media, providing extensive biological filtration.

   Tip: Monitor the water level in the sump to prevent the pump from running dry and getting damaged.

Filtration Methods and Materials Explained

There are various filter media used in combination with a filter. Each material has a specific function. Here are the most commonly used materials:

1. Filter Floss (mechanical filtration)

Filter floss, also known as filter sponge or filter wadding, is used for mechanical filtration. This material traps suspended particles such as food remnants, fish waste, and plant debris. It acts as a first barrier, keeping the water clear.

Tip: Replace or rinse the filter floss regularly to maintain its effectiveness. Dirty floss can block water flow. Always rinse filter floss in a bucket filled with aquarium water.

Depending on the amount of dirt, rinsing 1 to 2 times a year is often sufficient. As soon as you notice the filter's flow decreasing, this is a good indicator for maintenance.

2. Activated Carbon (chemical filtration)

Activated carbon is used for chemical filtration. This material can remove harmful substances such as chlorine, medications, and unpleasant odors from the water. It works by binding these substances through a process called adsorption.

Tip: Activated carbon becomes saturated over time, so replace it regularly, usually every 4 to 6 weeks, to prevent it from losing its effectiveness.

3. Peat (chemical filtration)

Peat is used to soften the water and lower the pH value, which is especially important for fish that require acidic and soft water, such as discus fish or certain types of tetras. Peat releases natural humic acids that soften and slightly color the water.

Tip: Use peat in combination with a filter basket in your external filter to improve flow and replace it when it loses its effectiveness.

4. Bio-balls (biological filtration)

Bio-balls are used for biological filtration. These plastic balls have a large surface area that is ideal for the development of beneficial bacteria. These bacteria help break down ammonia and nitrite, improving water quality and promoting a stable ecosystem.

Tip: Bio-balls do not need to be replaced often, but rinse them in aquarium water if they get dirty to preserve the bacterial culture.

5. Ceramic Rings (biological filtration)

Ceramic rings also provide a large surface area for beneficial bacteria. They are often combined with bio-balls in larger filters. These rings promote constant water flow and create an ideal environment for biological filtration.

Tip: Ceramic rings can become dirty over time, so rinse them during regular filter maintenance, but rarely replace them.

6. Zeolite (chemical filtration)

Zeolite is a mineral known for its ability to remove ammonia from water. It is often used in aquariums with a high biological load or during the start-up of a new aquarium.

Tip: Use zeolite temporarily when ammonia levels rise, and replace it when it loses its absorption capacity.

 

What to Consider When Choosing a Filter?

1. Capacity
   Choose a filter that matches the size of your aquarium. A good rule of thumb is that the filter should be able to filter the entire volume of your aquarium 4 to 5 times per hour.

2. Maintenance
   Regular maintenance is essential to keep the filter working optimally. Replace chemical filter media like activated carbon and zeolite on time and carefully clean biological materials with aquarium water.

3. Noise
   If your aquarium is in a quiet room, such as a living room or bedroom, choose a filter that operates quietly, especially external filters, which are often quieter than internal filters.

Combine Filtration Methods for Best Results

Many aquarium enthusiasts choose to combine multiple filtration methods for optimal results.

For example, an internal filter can provide mechanical filtration, while an external filter with bio-balls and ceramic rings handles biological filtration. Skimmers are often used for this purpose.

Please note that skimmers can produce noise due to falling water.

With the right choice of filters and filter media, you ensure that your aquarium finds a stable balance where its inhabitants will feel comfortable, and maintenance remains enjoyable.