Collection: Freshwater Filters for Clean Tanks

A fish tank filter is the life support system for your aquarium. Its primary purpose is to maintain a healthy and stable aquatic environment for your fish. This is achieved through three types of filtration:

• Mechanical Filtration: Physically removes solid debris and waste, like leftover food and fish waste, to keep the water clear. The filter sponge or floss traps these particles as water passes through.
• Biological Filtration: This is the most crucial type. A filter provides a home for beneficial bacteria that convert toxic ammonia (from fish waste) into less harmful nitrates. This process, known as the nitrogen cycle, is essential for preventing chemical build-up that can harm or kill your fish.
• Chemical Filtration: Uses media like activated carbon to remove dissolved impurities, odours, and discolouration from the water, enhancing clarity.

The "best" fish tank filter depends on a few factors, including your aquarium size, the number of fish, and your budget.

• Canister filters are ideal for large or heavily stocked tanks. They sit outside the aquarium, offering a large capacity for multiple types of filter media for comprehensive mechanical, biological, and chemical filtration. They are also discreet and powerful.
• Internal filters are perfect for smaller tanks (under 60 litres). They are compact, easy to install, and provide excellent mechanical and biological filtration.
• Sponge filters are simple, low-cost options often used for breeding tanks or with delicate fish like shrimp and fry. They provide exceptional biological filtration and gentle water flow.

For expert advice on choosing the perfect filter for your unique needs, our team at A1 Aquarium World are always happy to help.

Yes, a fish tank filter is essential for almost all aquarium setups. Without a filter, harmful toxins from fish waste, uneaten food, and decaying plant matter would rapidly accumulate. This toxic build-up of ammonia and nitrite would quickly poison the water, leading to stress, disease, and death for your fish. For most hobbyists, a reliable filter is the most effective and safest way to ensure a healthy, stable environment.

A canister filter is a powerful external unit that provides multi-stage filtration. Water is drawn from the aquarium through an intake tube and into the sealed canister. Inside the canister, the water is forced upwards through different layers of filter media:

• Mechanical Media: A coarse sponge or filter floss removes large particles.
• Biological Media: Water passes through porous ceramic rings or bio-balls, where beneficial bacteria colonies thrive and convert harmful waste.
• Chemical Media: Finally, media like activated carbon removes chemical impurities, odours, and discolouration.

The cleaned water is then pumped back into the aquarium through an outlet tube, ensuring a continuous cycle of comprehensive purification.

A sponge filter is a simple yet effective device that relies on an air pump for its function. An air stone or an airline from an air pump is placed inside a hollow tube within the sponge. The air bubbles rising up the tube create an airlift, which pulls water through the porous sponge.

• Mechanical Filtration: The sponge material physically traps and removes debris as water is drawn through it.
• Biological Filtration: The sponge itself provides a vast surface area for beneficial bacteria to colonise, which then perform the vital biological filtration process.

Because of their gentle flow and exceptional biological capacity, sponge filter systems are a staple for breeding tanks, shrimp aquariums, and quarantine tanks.

An internal filter is a compact, self-contained unit that is fully submerged inside the aquarium. These filters use a small pump to draw water directly from the tank into the filter's housing. Inside, the water passes through various filter media, typically a combination of sponge and a chamber for chemical or biological media. The cleaned water is then expelled back into the tank, often through a nozzle that provides a degree of water circulation. They are easy to install and maintain, making them an excellent choice for smaller tanks.

Proper filter maintenance is crucial to keep your aquarium healthy.

• Regular Cleaning: Depending on your tank's bioload, you should clean your filter every 2-4 weeks. To do this, simply remove the filter media and rinse it in a bucket of used aquarium water (water you’ve just siphoned out during a water change). Never use tap water, as the chlorine will kill the beneficial bacteria.
• Impeller Check: Annually, or if you notice a drop in flow, check the impeller (the small spinning fan inside the pump) for blockages or wear.

Replacing Media: Replace chemical media like activated carbon every 3-4 weeks. Sponges and other biological media should only be replaced when they are physically falling apart.

At A1 Aquarium World, we are dedicated to providing the highest quality fish tank filter products and expertise. We stock a wide range of top brands known for their reliability and performance, including Aqua One, Fluval, and Eheim. Our team of experienced staff are genuine hobbyists who can provide tailored advice on selecting the perfect filter for your unique needs and goals. We are here to help you get the best possible results for your aquarium.

The frequency of cleaning your fish tank filter largely depends on the size of your aquarium and the number of fish you have. As a general guide, you should perform a light clean every 2-4 weeks. This involves a quick rinse of the filter sponge and other media to remove trapped debris. For more thorough maintenance, such as cleaning the impeller and filter housing, a quarterly check is usually sufficient. Remember, the goal is to clean the filter without killing off the beneficial bacteria, so always use syphoned tank water to rinse your media.

Selecting the right filter size is one of the most important decisions you'll make. The key is to match the filter's flow rate (litres per hour) to your tank's volume. A good rule of thumb is to choose a filter that can process your tank's total volume at least 4-5 times per hour. For example, a 100-litre tank would need a filter with a flow rate of at least 400-500 litres per hour. Choosing an oversized filter is always better than choosing one that is too small, as it provides extra capacity for biological filtration and ensures excellent water clarity.