The best filter for 45 liter tanks

Clean water is essential to the health of your fish, no matter what size aquarium you have. Did you know that water containing even small levels of ammonia and nitrite can kill your fish? Weekly water changes are essential to keeping your tank safe for your pets, but an efficient mechanical and biological filtration system is also a must.

In this guide, we take a look at the best filter for a 45 liter tank, including our reviews and recommendations for the best products on the market today.

The 7 Best Filters For 45 Liter Tanks

An efficient filtration system is essential to keeping your aquarium clean.

Here are my seven recommended 45 liter fish tank filtration systems.

1. Tetra Whisper PF10 Power Filtration System

  • 90GPH
  • Three stage filtration
  • Absorbs odors.

Tetra is a well-known and highly respected brand in the fish farming hobby, producing high-quality fish food and associated fish aquarium products and accessories for over 50 years.

Tetra filters are inexpensive and readily available at good fish and pet stores, making them the preferred brand for beginners. Although they lack the multiple features and hype of some of the more expensive brands, Tetra filters are of decent quality and offer excellent value for money too. Filter media is included, but it’s very poor quality, so you may want to purchase your own.

The PF 10 is a power filter that hangs at the rear of the tank. The mechanical element of the system produces an impressive 90 GPH flow rate, which is perfect for a small 45 liter tank. The biological part of the system is pretty good too, although you can change the media if you want. On the downside, the pump is quite noisy compared to higher-end units, which could be a problem, depending on where you intend to keep your tank.

I recommend this filtration system for beginners looking for an inexpensive and reliable system that works.


  • Competitive price compared to many other similar units
  • Easy to clean and maintain
  • Generally reliable and durable
  • adjustable flow


  • Low quality biological filter media
  • Quite noisy compared to high-end filters

2. Whisper IQ Power Filter for Aquariums, with Silent Technology

  • silent aquarium filter
  • self-priming
  • Cartridge refills included

The entire unit has been redesigned and improved. The impeller is now stronger and more reliable, the cleverly designed weir helps agitate the water surface and oxygenate the tank, and the inlet tube is fully adjustable. You can alter the flow to suit delicate plants and fish that need calm water, and the integral BioGrid filters provide a large surface area on which aerobic bacteria can grow.

The Whisper IQ filter uses specially designed StayClean technology to save on maintenance and keep your aquarium water clean and healthy for your fish. The motor is protected by sound barrier and vibration dampening technology to make the filter super quiet, and improved materials mean the filter is built to last. This is one of the quietest, easiest to maintain and most efficient “back hung” filters on the market.

Overall this is a well made filter that is super quiet, very efficient and easy to maintain.


  • super quiet
  • Easy to clean and maintain
  • reliable and durable
  • Adjustable flow rate and inlet tube


  • Low quality biological filter media

3. penn plax internal cascade filter for aquariums

  • 70GPH
  • 2 filter media chambers
  • 1 refillable carbon cartridge and 1 biosponge

The Penn Plax Cascade is an affordable and efficient internal filtration system that is well made and gets the job done.

The unit draws 70 GPH of water through the dual filter chambers, helping to remove chemicals and other contaminants and creating a safe and healthy environment for your fish. If you’re a fan of carbon filters, you’ll appreciate that carbon is included in the cartridges, along with filter sponges that provide a large surface area where bacteria can grow.

The system is very quiet despite its power and also helps to aerate the water in your tank. On the downside, the force of the flow that the filtration system generates is quite powerful, which could be a problem for fish species that are poor or slow swimmers, such as goldfish and bettas. Unfortunately, the flow rate cannot be adjusted.


  • super quiet
  • powerful flow
  • reliable and durable


  • Flow rate is not adjustable

4. aqueon QuietFlow 10 internal power filter, up to 10 gallons

  • 66 GPH
  • Allows vertical or horizontal mounting
  • The filter is very quiet

The aqueon QuietFlow 10 includes mechanical, biological, and chemical filtration processes, so you can be sure your tank water stays clean and healthy for your live fish and plants. The filter media is very easy to maintain and the cartridges are easy to replace when needed.

This is an internal filter, so it does take up some space inside your aquarium, but the unit is quite small and relatively unobtrusive. Installation is done using suction cups supplied with the system. It is not necessary to prime the unit before use; just place it where you want it in your tank, plug it in and go.

The filter is very quiet, so you can confidently place your fish tank in any room in your home without fear of its presence being disturbed by a noisy pump, and your fish will not be disturbed by excessive vibrations.


  • powerful and effective
  • Perfect for small tanks
  • Efficient three-stage filtration
  • easy to maintain
  • too quiet


  • Not the same quality as other brands
  • Internal system takes up some space in your tank

5. Zoo with Nano External Canister Filter – 10 gal

  • 80 gallons per hour
  • Comes complete with spray bar system
  • Easy priming feature

If you are new to the hobby and looking for a filter system that will work well in a nano tank, the Zoo Med Nano might be for you. The filter pump is especially powerful, which is fine for nano tanks, and the unit has a spray bar that helps reduce flow intensity. The unit includes both a ceramic biological filter and carbon filter media.

This filtration unit is reasonably priced and the build quality is more or less what you’d expect for the budget range, although the length of the pipes and cables could be more generous. That said, the system is quiet and gets the job done in a small tank.

Overall, I think this filtration system is a great starter unit for a beginner who doesn’t want to spend a fortune getting their fish tank up and running.


  • Ideal for small tanks
  • efficient filtration
  • easy to maintain
  • too quiet
  • Good value for those on a budget


  • Doesn’t have the same build quality as more expensive alternatives

6. Marineland Penguin Biological Wheel Power Filter

  • 75 GPH (for aquariums up to 45 liters)
  • With rotating biological wheel
  • multi-stage filtration

The Marineland Penguin Power Filter has a lot to offer, including price, making this system affordable for all budgets. Plus, you get a three-year warranty on the filter, giving you peace of mind in the event of a problem.

The filtration system is very versatile and you can use it with both freshwater and saltwater setups. The three-stage cleaning system removes harmful ammonia and nitrites from the water, and the Black Diamond carbon filtration element removes impurities and odors, as well as keeping the tank water crystal clear. The newly remodeled BioWheel biological filter offers a very generous surface area for bacterial growth.

The filtration system connects directly to your intake tube, which means your aquarium enjoys good circulation throughout. The unit is easy to maintain and the installation is also very user friendly.

Overall, this is a great value product that gets the job done, and then some!


  • Great value for the price
  • three year warranty
  • easy to maintain


  • noisy operation
  • Replacement filters are expensive

7. Seachem Laboratories tidal energy filter 35

  • self-priming pump
  • self-cleaning impeller
  • surface skimmer

Seachem ‘s Power Tidal Filter is packed with features that give you an extremely efficient filtration system. The filter lid has cleverly designed ventilation slots and aeration slots that maximize gas exchange and ensure that the water returns to the tank fully oxygenated.

Instead of messy filter cartridges, the unit has a huge filter basket that is designed to take the filtration media of your choice, and the pack also comes with Seachem’s Matrix Biological Media to get you started.

The design of the filter system means that the water is pushed up from the bottom of the basket, ensuring that it comes into contact with the filter media, which is not always the case with other systems. When the filter media requires cleaning, a blue maintenance alert on the top of the filter tells you.

This unit has a surface skimmer that traps water just below the surface, collecting fish oils and floating debris. You can adjust the flow between the subsea inlet and the surface skimmer. Other impeccable design features include a self-priming pump and self-cleaning impeller that is suitable for use in both fresh and salt water tanks.

Additionally, there is a handy heater clip on the side of the filtration unit, ensuring that the water from the heater is evenly distributed throughout the tank.

You get a free three-year warranty, which you can extend to five years when you register the filter with the manufacturer.


  • Great value for the price
  • Three-year extendable warranty
  • easy to maintain
  • Customizable filter media
  • Lots of extra features


More expensive than other systems

Why Do You Need An Aquarium Filter For A 45 Liter Tank?

Many people assume that a small fish tank does not need a filtration system. After all, a few fish won’t make much of a mess, right? Nope!Every tank needs a filtration system, no matter how many fish the aquarium contains and how large the setup is. That’s due to a biological process known as the nitrogen cycle.

The nitrogen cycle

In the natural environment, levels of ammonia, nitrite, and nitrates rarely rise to levels that are dangerous to wildlife. However, your freshwater fish tank is a “closed environment” that often contains a large number of fish and invertebrates, all of which contribute to the toxin load in the water. If the level of nitrogenous compounds in the water becomes too high, the fish become sick and stressed, leaving them vulnerable to disease and even death.

Keeping live plants in your setup can help remove nitrates from the water column and use them as nutrients. However, you will need to maintain water quality by performing weekly partial water changes and installing and maintaining an efficient biological filtration system to manage the nitrogen cycle.

A biological filtration system provides an area in which beneficial bacteria can grow. Those bacteria break down harmful ammonia and nitrites produced by fish waste and decaying organic matter, turning them into less dangerous nitrates.

carbon dioxide and oxygen

Fish and invertebrates breathe in oxygen and exhale carbon dioxide (CO2). Living plants use CO2 during the day and produce oxygen, but at night the process is reversed. As long as the CO2 level in the water remains below 32 ppm, your fish will be safe. However, if the CO2 level gets too high, the water becomes toxic to the fish and you will see symptoms such as lack of appetite, lethargy and the fish may start panting at the surface of the water.

You can increase the oxygen levels in your water using an air stone and a pump, but a good mechanical filtration system will also help oxygenate your water.

What Size Filter Do You Need For A 45 Liter Tank?

Choosing the correct size filter for your tank is vital for the unit to work efficiently and keep the water clean and well-oxygenated, and the key to look for is the flow rate the filter unit provides.

The flow rate of aquarium filtration units is measured in GPH or gallons per hour. In other words, the number of gallons of water that pass through the filter pump in one hour. I recommend that you use a filtration unit with a GPH of at least four times the capacity of your aquarium.

So if you have a 45 liter tank, you will need a filtration unit with a flow rate of at least 40 GPH. However, I always use a stronger filter than that if possible. A powerful filtration system keeps the water moving around the aquarium and over the biomedia, ensuring the beneficial bacteria in the filter stay well oxygenated and preventing stagnant areas from developing in the tank.

Types Of Filters For A 45 Liter Tank

There are three methods to filter your tank water:

biological filtration

Biological filtration is the process by which certain bacteria break down harmful ammonia and nitrites into a less toxic nitrate compound. These bacteria require a surface on which to grow, such as filter sponges, substrate, and rocks. Biological filtration is often more effective when used in combination with another method.

chemical filtration

The chemical filtration process typically uses activated carbon to remove dissolved waste products from the water, and is typically part of a combined filtration system along with biological and mechanical filters.

mechanical filtration

Mechanical filtration uses a pump system that circulates the water around the aquarium, drawing solid debris particles out of the water through some type of filter. Although mechanical filtration will help keep the water clean and remove general floating debris, the process alone does not remove potentially hazardous substances from the water. Mechanical filtration also aerates the water.

For a mechanical filtration system to work efficiently and effectively, it must circulate the water around the tank at least four times per hour.

What To Look For In An Aquarium Filter For A 45 Liter Tank

In addition to good flow rate, as mentioned above, you should also check biomedia capacity and consider filter cartridges when choosing your filtration system.

Biomedia Capacity

Remember that it takes millions of bacteria to process just a small amount of fish waste, so look for a filtration system that contains a great biological element.

Specifically, you want a system that contains as much biomedia as possible. Think about the nitrogen cycle and you know that the more bacteria you have, the cleaner your tank will be in the long run. So the more surface area that is available for bacteria, the better.

Filter cartridges: what is the big problem?

Many filtration systems come with filter cartridges that are loaded into the unit. Filter cartridges are usually made of activated carbon that is sandwiched between two thin layers of coarse cloth.

The filtration unit’s pump draws water through the cartridges, which provide a platform where bacteria can grow. At the same time, the fabric traps fish and debris particles from the water, and the carbon removes chlorine, tannins and other harmful chemicals.

Is carbon really necessary?

Whether carbon is really necessary for an aquarium filter system is debated. Carbon filters medications, so if you are treating your fish for a disease, such as Ich, you should remove the carbon from the filtration system. Obviously, if your system uses filter cartridges, it will also remove the biological element, which could allow ammonia and nitrites to build up in the tank, disrupting the entire ecosystem.

Also, carbon is only effective for a few weeks, and then you have to replace the cartridges. That means throwing out the entire cartridge, including the beneficial bacteria you’ve worked so hard to cultivate!

Disadvantages of filter cartridges

Personally, I don’t like filtration systems that use cartridges. First, the drives can be extremely messy and messy to clean and maintain, and second, the cartridges themselves are generally very expensive. I recently switched to using simple box filtration systems that contain only sponges. The sponges provide enough area for bacterial colonization and the units are much simpler, faster and cheaper to maintain.

I also hate waste and throwing away used filter cartridges every few weeks just didn’t sit well with me. However, if you want to include chemical filtration in your system, cartridges are probably the way to go.


I hope you have enjoyed our guide to choosing the best filter for a 45 liter aquarium.

Of the products featured in our guide, our highest rated filtration system is the Seachem Laboratories 35 Tidal Power Filter. This premium quality filtration system has been designed with a host of great features that make maintaining and operating the unit very easy and hassle free, as well as ensuring crystal clear, healthy water for your fish.

The massive filter basket can be filled with the media of your choice, and there’s even an indicator to tell you when to clean the unit. The only real downside to this filter unit is that it is in the higher price range. That said, you get a great quality kit that can be used in both fresh and saltwater tanks, and it also comes with an extendable three-year warranty.

If you’re on a more limited budget or new to the hobby, you may prefer to go with the Marineland Penguin Bio-Wheel Power Filter. This system offers excellent value for money and while it doesn’t have the range of features offered by our top pick, the unit still offers performance, ease of maintenance and also comes with a three year warranty.

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