Updated: January 4, 2021 - By: - Categories: Equipment

When you begin setting up your aquarium you know that you need to filter the water but there are many, many types of aquarium filter systems to choose from. In the tank? Outside of the tank? Small? Large?

Perhaps you already have a well-established aquarium and you’re just thinking about upgrading your filtration. There are still many options and varieties to choose from and I have no doubt that this set of pages will be of use to you in making your selection.

Best aquarium filter comparison table

Model Our rating Type Flow rate For tank Filter media Others
Marina S10 Power Filter editor's ratingMarina S10 Power Filter #ad Hang-On-Back 55 GPH, adjustable up to 10 gallons filter cartridges with included carbon & zeolite intake pre-filter sponge
Aqua Clear 20 power fish tank filter editor's ratingAqua Clear 20 power fish tank filter #ad Hang-On-Back 100 GPH, adjustable 5-20 gallons Foam, Activated Carbon, and BioMax
Tetra Whisper 20 Power Filter editor's ratingTetra Whisper 20 Power Filter #ad Hang-On-Back 105 GPH, adjustable 10-20 Gal bio-foam, large Bio-Bag cartridge
MarineLand Penguin 350 BIO-Wheel Power Filter editor's ratingMarineLand Penguin 350 BIO-Wheel Power Filter #ad Hang-On-Back 350 GPH 50-70 Gal filter cartridge with included carbon rotating bio-wheel for wet/dry biological filtration
Fluval U4 Underwater Filter editor's ratingFluval U4 Underwater Filter #ad internal filter 260 GPH, adjustable 34-65 Gal 2 foam pads, 2 poly/carbon cartridges, and 90 grams BioMax 3-way flow control, adjustable
Penn Plax Cascade Black 1000 Elite Canister Filter editor's ratingPenn Plax Cascade Black 1000 Elite Canister Filter #ad canister filter 265 GPH, adjustable up to 100 Gal Bio-Sponge, Bio-Floss, Pro-Carb, Bio Rings assembling components, algae magnet
Fluval 307 Performance Canister Filter editor's ratingFluval 307 Performance Canister Filter #ad canister filter 206 Gal/h (780 L/h) 40-70 Gal (90-330 L) bio-foams, ceramic rings, activated carbon 3 media baskets and assembling components
Fluval FX4 canister filter editor's ratingFluval FX4 canister filter #ad canister filter 700 US Gal/h (2650 L/h) up to 250 US Gal (1000 L) bio-foams, ceramic rings, activated carbon multi stackable media baskets, 1 US Gal (3.9 L) total media capacity
Polar Aurora 266GPH canister filter with UV sterilizer editor's ratingPolar Aurora 266GPH canister filter with UV sterilizer #ad canister filter 265 GPH (1000L/h), adjustable up to 75 Gal activated carbons, ceramic rings, bio-balls spray bar, 3 media trays, 9W UV sterilizer

How do aquarium filters work?

Before you decide on what filter you want to use, it is important to have a basic understanding of how aquarium filters work! The aquarium filter is usually powered by a pump that draws the water from the tank into its filter chamber containing filter media for purification.

There are three types of filter media that are correspondingly related to three types of filtration – mechanical, biological, and chemical.

Filtration type Filter media Role
Mechanical sponges #ad (foam), floss pad #ad, pre-filter media #ad physically removes debris and floating particles, prevent clogging
Chemical peat moss #ad, activated carbon #ad (charcoal), phosphate remover #ad, zeolite ammonia remover #ad, Fluval Zeo-Carb #ad purifies the water by directly absorbing substances such as odorants, heavy metals, minerals, phosphate, ammonia…
Biological Biomax ceramic rings #ad, bio sponges #ad, bio balls #ad, Eheim Substrat Pro #ad, coral bone stone… colonizes helpful bacteria that convert toxic ammonia and nitrite to less toxic nitrate

1. Mechanical filtration

This is usually the first stage of filtration. Mechanical filtration means physically removing debris and other floating dirt particles in order to keep the water crystal clear.

Generally, filter media like filter wool or ceramic rings are used for mechanical filtration. Fine filter wools are used to catch fine particles whereas ceramic rings capture coarse particles before they clog up finer filter material.

By filtering out particulate matter mechanical filter media protect biological and chemical filter media from coarse debris and increase their lifetime. Mechanical filter media must regularly be rinsed or renewed in order to prevent clogging up.

2. Biological filtration

Biological filtration is the recycling of harmful chemical substances by bacteria. Fish waste such as urine, feces, and respiration byproducts pollute water chemically with toxic substances such as ammonia. Ammonia is very poisonous to fish especially at high pH levels.

The recycling bacteria colonized on the surfaces of the biological filter media convert ammonia into much less toxic nitrate. This conversion – ammonia to nitrate – is called the nitrogen cycle. If the aquarium is new it may take several weeks or even months before the bacteria reach a sufficient population.

aquarium-nitrogen-cycle

Aquarium nitrogen cycle

Typically, porous filter media like ceramic rings are used for biological filtering due to their huge surface area to volume ratio. Biological filter media should be rinsed with aquarium water in order not to harm recycling bacteria. Recycling bacteria colonize not only filter media but every possible surface in the aquarium such as gravel, rocks, and plant leaves.

3. Chemical filtration

Activated carbon is commonly used as a chemical filter media in aquarium filters because it absorbs large molecules such as many organic substances and medicaments. This keeps the water clear and free of odors.

Peat as a chemical filter medium is widely used to reduce and stabilize pH (acidity) levels for keeping and breeding soft water species. To accomplish this job peat does not actually filter out or convert anything; it releases humic acids which increase acidity and reduce carbonate hardness.

Other commercial media like phosphate remover, ammonia remover,… may also count as chemical filter media as they remove harmful chemical substances from the water.

Most popular aquarium filter types these days

Once you have gotten past the decision of what type of filtration you want to use, there are several options and specs when looking at specific types of filters. The following sections will help you have an overall look about different types of filters available in the market these days.

Sponge and corner filter (air-driven)

AQUANEAT Sponge Filter (classic form)AQUANEAT Sponge Filter (classic form) #ad

Hygger Double Sponge aquarium filterHygger Double Sponge aquarium filter #ad

AquaCity corner filterAquaCity corner filter #ad

Aquapapa Corner FilterAquapapa Corner Filter #ad

Sponge and corner filters with their different variations are usually powered by an aquarium air pump. The air pump injects air into the filter, the air then rises out of the water making a force drawing the surrounding water into the filter’s chamber for filtration.

They are the most simple of the aquarium filters and are commonly used in breeding tanks and while raising the fry. Occasionally they are an affordable option for very small tanks if the tanks are understocked with very small and delicate fish and/or invertebrates.

Air-driven filters have some benefits for delicate situations but for most aquariums, this is not the best choice for your main filtration system. They provide very limited filtration all around that are only suitable for very specific situations, though they do function well as supplemental biological filtration in addition to the use of a more advanced system.

Undergravel aquarium filters (air-driven)

Penn Plax CFU55 Premium Under Gravel Filter SystemPenn Plax CFU55 Premium Under Gravel Filter System #ad

A step up from the sponge filters but still a very simple system. The undergravel filter is usually placed under an average-sized gravel substrate and works by drawing the water down through the gravel, which plays the role of mechanical and biological filter media.

Like the sponge filters, chemical filtration is minimal if it is incorporated at all. The biological filtration and mechanical stages of filtration, however, are definitely an upgrade from the sponge filters.

Undergravel filters can provide adequate filtration by themselves in smaller aquariums that are very lightly stocked with fish. In most cases, undergravel filters will be much more beneficial in supplementing biological and mechanical filtration in any aquarium when used with more advanced systems.

Power filters / (HOB) Hang On Back filters

Aqueon QuietFlow power filterAqueon QuietFlow power filter #ad

HOB filters are probably the most common filtration systems purchased by aquarists that are just starting out. They are not a bad option by any means, they hang right on the tank’s rim with the bulk of the unit outside of the aquarium and they efficiently incorporate all three stages of filtration.

The power filter is powered by a water pump that draws the water from the tank through its intake tube into its internal filter media for filtration. The filtration efficiency depends on the internal filter media and the good water flow the pump generates.

The fact that they hang on the back of the tank saves on space compared to an external canister filter (below.) These are typically rated for 75-gallon aquariums on the high end and in most cases, I would recommend trying to avoid “maxing out” your filter’s recommended tank volume. (i.e. 75 gallon rated HOB = use for max 55-60 gallon aquarium)

It isn’t the very best option for filtration but it will get the job done and can absolutely be the only system used to filter your aquarium water.

Internal filters / internal power filter

Tetra Whisper 10i Internal FilterTetra Whisper 10i Internal Filter #ad

Powered by an internal water pump like the external power filter and the working mechanism is the same. Internal filters are great if you really don’t have the space between the tank and a wall for a HOB filter nor the room to put an external canister. Of course, the filter has to go somewhere! If you are saving space outside of the aquarium, you are sacrificing space inside.

These aquarium filter systems are fully equipped to handle your fish tank’s dirty water through the mechanical, chemical, and biological stages and they can certainly do so efficiently.

External canister filters

SunSun HW-302 265GPH Pro Canister Filter KitSunSun HW-302 265GPH Pro Canister Filter Kit #ad

This is quite possibly the best decision for filtering your aquarium. All of these systems are going to do a fantastic job filtering your aquarium water through all three stages.

Most external canister filter models are going to allow you to customize your filtration. There are many options for configuring your canisters filtration media to handle different mechanical, chemical, or biological filtration loads. It all just depends on the specific needs of your aquarium.

Aside from the ability to fine-tune your filtration, external canisters simply do a better job of filtering the water in all three stages over any of the above-mentioned types of aquarium filter systems.

If you buy a quality canister filter, you won’t need to replace it for a very long time. It will run quietly, and you will have continuously crystal clear water and consistent water parameters.

Trickle (Wet/Dry) Filter

Trickle box filterTrickle box filter #ad

Wet/Dry sump filterWet/Dry sump filter #ad

This filter trickles the water down through bio-media (usually bio balls) for the best aeration and biological filtration. It is powered by a water pump. The pump draws the water from the tank to the filter box (if placed above the tank, left picture) or returns the filtered water from the filter box to the tank (if placed below, usually in a sump, right picture).

Although providing the best filtration, the trickle filter isn’t commonly used because of its bulky and unsightly components.

Wet/dry sump-style systems are popular in saltwater aquariums because they aggressively oxygenate the water, and oxygen is much more important in saltwater environments. They also provide a great place for housing macroalgae, live rock, and equipment that you want to hide from view. However, they tend to be fairly expensive, so are not used in freshwater aquariums much.

How to choose the right aquarium filters?

aquarium-filter-choosing

When you have settled on what type of filtration will work best for your ideal setup, the detailed pages that I just mentioned include comparisons of several brands, models, and sizes for each type of filter; All in hopes of helping you make the best choice for your unique freshwater aquarium!

Besides choosing a filter type you want, you will need to know how to choose a suitable filter for your aquarium. This depends on the size of your tank and the species of fish it houses.

The thumb rule is to choose a filter that turns over four times of your aquarium water in an hour. For example, a 20-gallon aquarium will need a filter with a flow rate of around 80 gallons per hour (GPH)

A too weak filter can’t circulate your aquarium well, which will end up the health problems of your fish. And vice versa, you can’t really over filter your aquarium.

Having a filter that is much too powerful for the size of your aquarium is only negative in the sense that the output flow from the filter will be too strong. This may cause stress and kill your fish, as well as destroy the beautiful aquascape that takes you a lot of time to fulfill.

All aquariums are very different which means that the best aquarium filter systems for your fish tanks will unlikely be the same as the best means of filtration for my fish tanks. Some fish love strong water flow while some like Bettas enjoy swimming slowly in a quiet environment. And your work is to provide the right environment for your aquatic pets.

Getting the best quality filtration system for your aquarium can save you from a lot of future hardship. (ammonia spikes, sick or dead fish, easier maintenance…) And it’ll help keep the water looking crystal clear for much longer!

Getting the cheapest filters can cost you more money in the long run. (More frequent media changes, more frequent water changes, malfunctioning equipment, you upgrade down the road anyway…)

Reviews of some of the best fish tank filters

Marina Slim S10 Filter for tanks up to 10 gallons

The Marina Slim S10 filter is designed to fit aquariums up to 10 Gal (38 L). It is the first in a three filter series, followed by the Marina Slim S15 (71 GPH, for 15 Gal tanks) and the Marina Slim S20 (92 GPH, for 20 Gal tanks).

The slim design of this filter is great for those who are looking to create a minimalist nano tank look. It takes up about half as much space in comparison to other filters with the same flow rating, giving your home aquarium a sleek, sophisticated look.

It’s easy to install right out of the box and comes with an adjustable flow control allowing for the perfect flow to suit your needs.

The most unique feature of this filter is that the motor is submerged in the water, minimizing loud motor noise and makes the filter self-priming. This comes in handy when doing weekly maintenance or in case of a power outage.

Bio-Carb and Bio-ClearBio-Carb and Bio-Clear #ad

It comes with two filter cartridges; 1 Marina Bio-Carb, and 1 Marina Bio-Clear, each filled with Marina’s Ceramitek biological media. This highly porous media is specifically designed to optimize your biological bacteria growth to ensure your aquarium stays healthy.

It also comes equipped with a pre-filter sponge, which fits the intake tube, to prevent sucking up any small fry or shrimp into the filter.

Aquaclear 20 power filter for 5-20 gallon fish tanks

The Aquaclear 20 power filter is a great option for those who are looking for a hang-on filter with a large filtration capacity and a high flow rate. With its multi-stage filtration, powerful motor, and quiet waterfall design, the Aquaclear 20 power filter has been top-rated for the past 50 years.

Its powerful motor is designed to move 7 times the amount of water than other filters of the same size. It also has an adjustable flow valve, allowing you to adjust the flow for your aquarium needs.

Multi-stage filtrationMulti-stage filtration #ad

This filter is designed to increase the filtration contact time with its three filter cartridges; one Foam Pad (mechanical), one Activated Carbon (chemical), and one Biomax (biological). It also comes equipped with a filter basket that prevents the water from bypassing the filters, allowing for maximized filtration.

Aquaclear has developed an entire filter media product line including Zeo-Carb and Ammonia Remover, allowing for an easy swap of chemical filtration to directly affect the needs of your aquarium.

Tetra Whisper 20 power filter for 10-20 gallon tanks

In terms of convenience and simplicity, the Tetra Whisper Power Filter is high on the list. With its Bio-Bag filter cartridges, it makes filter replacing as simple as tossing the old one and replacing it with the new.

As the name indicates, this filter is designed with an easy to clean motor that pushes the water through the filters, then gently waterfalls back into the aquarium. It also has a convenient adjustable flow valve, giving you the option to reduce the flow during feeding time.

The Bio-Bag filter cartridge is made up of a double-sided mesh mechanical filter and filled with ultra-activated carbon, making it a suitable filter for freshwater aquariums. You can purchase these filter cartridges either pre-assembled or unassembled at half the cost.

Partnered with the Bio-Bag is BioFoam, a three-dimensional foam pad that provides a large surface area for healthy bacteria growth.

This filter’s simple, yet effective design makes it easy to clean, and with its low price point is a great option for beginner hobbyists.

Marineland Penguin 350 Bio-wheel power filter

The Marineland Penguin 350 is a wonderful option when setting up larger aquariums of 50 to 75 gallons in size. With a powerful and quiet motor, it provides a flow rate of up to 350 GPH.

This filter comes equipped with two Rite-Size C cartridges, two Bio-Wheel filters, and an intake tube with an intake screen and extension intake tube. It’s also designed to have ample room, fitting up to four Rite-Size C cartridges and additional space for a refillable media cartridge (Penguin 200/350 only, sold separately).

Bio wheelsBio wheels #ad

The most unique aspect of this filter is its dual wet/dry Bio-Wheel setup. This biological filter increases the growth of nitrifying bacteria by spinning and exposing them to more oxygen. Resulting in healthier and more active beneficial bacteria to break down ammonia and nitrite.

Rite-Size C cartridgeRite-Size C cartridge #ad

Refillable media cartridgeRefillable media cartridge #ad

Marineland designed their Rite-Size C cartridge with a poly filter and a ribbed plastic pad, filled with activated carbon, providing you with ample mechanical and chemical filtration. The cartridge is refillable with its special design. The refillable cartridge (sold separately) gives an abundant place for housing filter media of your choice

For a larger filter, the Marineland Penguin 350 is still easy to use and clean. All parts are removable, making your weekly and/or monthly maintenance quick and simple. It would make a great filter for freshwater or saltwater setups.

Fluval U4 underwater filter for 55-60 gallon tanks

If you are looking for a versatile, compact, yet highly effective internal filter, then look no further than the Fluval U Series underwater filters. It has a three-stage filter system, a foam pad, a poly/carbon cartridge, and Biomax ceramic media. Making them suitable for fresh, marine, and reptile aquariums.

These filters have an adjustable three-way flow control feature (U2, U3, and U4 only), allowing you to use three different water output positions, to create the ideal flow for your specific aquatic environment.

One at the top of the filter for maximum aeration and circulation, a spray bar to create a gentle and even water flow suitable for planted aquariums, and one at the bottom suitable for shallow aquariums.

The Fluval U Series filter has a convenient flip lid on the top, making changing filter media quick and easy.

This filter also has the ability to be installed either horizontally, for shallow water aquariums, or vertically against the side of the aquarium to create currents and flow patterns to suit your specific needs.

Penn Plax Cascade Black 1000 Elite Canister Filter

This filter is identical to its original version, the Penn Plax Cascade Blue #ad, but comes with some extra filter media and has a solid black exterior, instead of blue and black.

Both the Cascade and Cascade Elite come with a Bio-Floss filter (for small particle matter), a Bio-Sponge (for larger particles and larger surface area for bacteria), and a Pro-Carb filter (for chemical filtration).

The Cascade Elite also comes with your first set of filter media with the addition of Bio-Rings media, a complete set of replacement filter media, as well as a Magna Sweep Algae Magnet, being a choice buy for those on a budget.

It has two flow-control valves, one on the water intake line and another on the water return line. This allows for easy control of the flow rate, as well as easy to detach hose lines during maintenance.

It also comes with an easy push-priming button, pulling water from the aquarium while you press to fill the canister. Making this filter easy to use and highly effective.

Fluval 307 Performance Canister Filter for 40-70 gallon tanks

The Fluval 07 Performance Canister Filter is the 7th reincarnation of Fluval’s top-selling canister filter. With some recent upgrades, this filter is one of the most powerful, most quiet, and energy-efficient filter on the market today.

This latest version has a newly designed Italian Precision-Crafted Pump, which makes this filter up to 25% quieter than its earlier models. Plus with the addition of rubber feet stabilizers, offers a more stable base and less vibration.

The 07 series is a powerful filter but is remarkably energy efficient. Depending on the model, it can draw as little energy as 10 to 23 watts. That is the equivalent of a single household LED light bulb.

Aquastop valvesAquastop valves #ad

Lift-Lock Motor Head ClampsLift-Lock Motor Head Clamps #ad

Maintenance is made easy with a newly designed Aquastop valve, easily removable Lift-Lock Motor Head Clamps, EZ Lift Media Baskets, and a simple Quick Primer. Reducing your time spent cleaning by half.

Filter media basketsFilter media baskets #ad

The media baskets inside these filters are designed to utilize every square inch of volume possible, to increase the surface area of filtration while still being compact. The filter components are smartly placed for easy access for cleaning and maintenance.

Inside is separated into four independent chambers, each filled with a different media. First in a vertical position is the Bio-Foam Max and Bio-Foam pre-filters. Then laying in horizontal filter baskets are Bio-Foam+, a Carbon filter pad, Biomax ceramic media, and topped off with a Quick Clear polishing filter pad (only with the 207, 307, and 407 models).

Fluval FX4 canister filter for extra-large fish tanks up to 250 Gal

The Fluval FX Series canister filters take in-home aquarium filtration to a professional level.

Their patented smart pump technology features an electric circuit board that monitors impeller speed and constantly measuring energy efficiency. It also pauses the filter every 12 hours, allowing the release of any trapped air, ensuring the filter is filtering as efficiently as possible.

The smart pump technology also has an auto-start and self-priming feature, just fill up the canister with water and turn it on, and the filter will purge the air and start running on its own.

Multi-functional utility valveMulti-functional utility valve #ad

At the base of the filter is a multi-functional utility valve that makes emptying the canister and performing water changes directly from the valve, without the hassle of multiple hoses. It also has convenient hose clips on top of the filter for easy storage.

Multi-stage filtrationMulti-stage filtration #ad

Among all the amazing features of these filters is its multi-stage filtration system. Both models come with multiple, stackable filter baskets, designed to fit snuggly inside the filter to reduce water bypass.

The large capacity of these filter baskets makes it so you have 4 stages of filtration in the FX4, and 6 stages in the FX6. The media includes foam filters (x4 in FX4, x6 in FX6), Bio-foam filters (x1 in FX4, x2 in FX6), 2 Bio-Max ceramic media, 1 carbon foam filter, and 1 refillable media bag.

Polar Aurora 266 GPH Canister Filter with UV sterilizer

The Polar Aurora Canister Filter is a wonderful option for those who are looking for a simple, high flow canister filter, that doesn’t cost over 100 dollars.

It has a lot of the same features as other comparable filters, such as a self-priming pump, three easy to remove filter baskets with mechanical, biological, and chemical filtration, and an easy-disconnect valve for easy maintenance.

There is one feature of these canister filters that is very unique, it incorporates the use of a 9watt Ultraviolet light (266gph, 370gph, and 525gph models only).

This fourth stage of filtration helps remove single-celled organisms from the water with UV radiation, helping with algae control and eliminates free-swimming parasitic organisms that can harm your fish.

The UV light is easy to access and replace, with the help of a viewport on top of the canister. It also comes with a quartz sleeve that protects it from water damage.

In The End

Filtration comes in a handful of different forms and there are a ton of brands, models, and varieties within the different aquarium filter systems. If you’re looking at a page full of filters and prices, it can be overwhelming.

But it doesn’t have to be overwhelming!

I will leave you with my 2 biggest pieces of advice regarding your decision.

First: Make sure that your filter incorporates the 3 types of filtration (Mechanical, Biological, and Chemical) efficiently enough for your setup. Primarily basing what is efficient enough on the volume of your tank.

Second: Equip yourself as best as you can, after all, aquarium filter systems are pretty much the backbone of your aquarium. Without filtration, you do not have an aquarium, you have a glass case of water with dead things in it!

Lucas has been keeping successful fish, planted, and reef tanks for many years. He loves to collect aquatic organisms and keep as many aquariums as he can.

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