What The Best Internal Aquarium Filter You Can Buy

Best Internal Aquarium Filter You Can Buy

An aquarium filter is crucial in fishkeeping to keep the tank clean, clear, and healthy for the inhabitant and Internal filters are one of its types.

Internal filters remain fully submerged in your aquarium water. It is the perfect solution if you can’t afford a canister or hang-on-back (HOB) filter because of space constraints. They are also quite useful and can deliver effective filtration at a much lower price.

You can use internal filters as a standalone filter for small fish tanks or as a backup filter for larger tanks. But, what are the best internal aquarium filters you can buy?

We have had a closer look at several internal filters and handpicked the top 5 in the market. In summary, here are the best internal filters to buy in 2022.

Most internal filters are quiet and run very smoothly. They are also easy to install using suction cups or brackets that come with the package and require simple maintenance. 

Quick Comparison Of Top Three Internal Aquarium Filter

Best Of The Best
Fluval U4 Underwater Filter, Freshwater and...
Runner-Up
COOSPIDER Sun JUP-01 Aquariums in Tank Submersible...
Best On A Budget
Tetra Whisper Internal Filter 10 To 30 Gallons,...
Fluval U4 Underwater Filter, Freshwater and...
COOSPIDER Sun JUP-01 Aquariums in Tank Submersible...
Tetra Whisper Internal Filter 10 To 30 Gallons,...
$76.43
$49.99
$34.95
-
6,710 Reviews
2,006 Reviews
15,723 Reviews
Best Of The Best
Fluval U4 Underwater Filter, Freshwater and...
Fluval U4 Underwater Filter, Freshwater and...
$76.43
6,710 Reviews
Runner-Up
COOSPIDER Sun JUP-01 Aquariums in Tank Submersible...
COOSPIDER Sun JUP-01 Aquariums in Tank Submersible...
$49.99
2,006 Reviews
Best On A Budget
Tetra Whisper Internal Filter 10 To 30 Gallons,...
Tetra Whisper Internal Filter 10 To 30 Gallons,...
$34.95
-
15,723 Reviews

What Is An Internal Aquarium Filter & How Do They work?

The reason they call it internal is that it goes inside your tank. However, some filters remain outside, called external filters, like canisters or HOB (hang on the back) filters.

The media compartment contains all the necessary filtration elements. The filter pump sucks water from the tank and pushes the water to pass through the media chamber. Usually, internal filters contain filter cartridges to provide three-stage filtration; mechanical, chemical, and biological.

Additionally, some brands include UV lights and special algae pads that are capable of preventing algae growth. The most common outflow pattern from the filter is the waterfall; some also use spray bars to evenly distribute the flow.

Internal filters are capable of creating bubbles because it has the provision to suck air from outside. So, while using an internal filter, there is no need to use an air pump because it can oxygenate the water itself.

How to Use an Internal Aquarium Filter? 

To understand the basic operation and get the idea of using an internal aquarium filter effectively, I highly recommend watching the video until the end.

The 05 Best internal aquarium filter review

Fluval U4 Underwater Filter, Freshwater and...
6,710 Reviews
Fluval U4 Underwater Filter, Freshwater and...
  • Use as a primary filter for smaller aquariums, or supplementary filter for larger aquariums
  • Sleek design with easy grip water control panel and redesigned media cartridge to trap more debris
  • Convenient flip-top lid allows for quick and easy access to filter cartridge for maintenance or replacement
  • Position horizontally for shallow tanks, larger tanks with low water levels, or to create a decorative waterfall feature...
  • Designed for freshwater, saltwater and reptile environments up to 65 gallons

Fluval U4 has so many unique features that make it my favorite internal filter. Fluval is a renowned brand for making aquarium filters and other equipment. This one is also not an exception, a high-quality submersible filter suitable to use up to 65 gallons.

Amazingly, Fluval U4 has 3-way flow output. One is from the top for maximum water circulation and oxygenation. Another one is from the middle, and it’s actually an integrated spray bar that provides an even and gentle flow. The last is from the bottom for deepwater agitation. The most important part is that you can adjust the flow according to your tank needs.

Another exciting feature is that it can be placed horizontally as well. The horizontal placement option also makes it suitable for low water tanks, and you can create a decorative waterfall.

It has a three-stage filtration system. You can remove the cartridges from the top access without dismounting the filter. It’s super simple to install and straightforward to maintain. In addition, this internal filter is super quiet, and you cannot hear almost anything while it’s running.

Apart from being a bit pricey, it has no downside, in my opinion. If you want to buy a quality product, it’s an excellent value for the money. In addition, you can use it as a standalone filter for the recommended aquarium size and a supplementary backup filter for larger aquariums.

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Pros
  • Three-stage filtration system
  • 3-way adjustable flow
  • Super quiet
  • It can be positioned both vertically and horizontally
  • Suitable for freshwater, marine water, and reptile tank
  • Easy access to replace filter cartridges
Cons
  • A bit expensive

COOSPIDER Sun JUP-01 Aquariums in Tank Submersible...
2,006 Reviews
COOSPIDER Sun JUP-01 Aquariums in Tank Submersible...
  • 【Important Note】After receiving the product, must remove the shock-proof sponge inside the product before using it....
  • 【Warm Prompt】Since this product contains a small motor to drive the water circulation, there will be a loud motor...
  • 【Product Detail】Size: 3.5" L X 3.9" W X 12" H, Cord: 4.6ft., Flow rate: 210 gallon per hour, suitable for 40-80...
  • 【Warm Tips】In order to maintain the best cleaning effect, it is recommended to check the machine every 1-2 weeks:...
  • 【1 Year Warranty】If any questions or problems, please contact the service mailbox on the package, we will solve and...

COOSPIDER Sun JUP-01 submersible filter has gained so much popularity among aquarists. So many users mentioned they had solved algae issues in their tanks with the built-in UV bulbs of this internal filter.

UV sterilizers are very handy to kill unwanted bacteria, viruses, and algae in a fish tank. However, you should not keep the bulb on all the time; otherwise, it may reduce the lifespan of the bulb. You should generally open the UV sterilizer only for 30 to 60 minutes, depending on the tank conditions.

This is a versatile filter, and you can use it in any aquarium, including freshwater, saltwater, or turtle tank. It’s suitable to use in aquariums ranging from 40 to 80 gallons.

Along with the primary filter, it comes with two filter cartridges and one spare UV bulb. So, basically, you don’t need anything extra to set up, and you can use it directly in your aquarium. But, remember to submerge completely in the water.

Like all other internal filters, this one also creates microbubbles; however, you can adjust the bubble amount by regulating the airflow. Meaning you can easily use it in aquariums where a gentle water flow is needed.

I highly recommend this COOSPIDER Sun JUP-01 if you want your money well spent and a crystal clear aquarium; with no cloudiness and no algae. The manufacturer also provides a 1-year warranty for their product.

The downside, it’s comparatively more expensive than other internal filters, and some users find it difficult to understand the instruction manual. Still, the images on the package are self-explanatory.

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Pros
  • Built-in UV sterilizer
  • Efficient in clearing cloudy and green water
  • Suitable to use in all aquariums
  • Remove and prevent algae
  • 1-years of product warranty
  • The amount of bubble is adjustable using a simple knob.
Cons
  • Relatively pricey
  • A very few find it difficult to understand the instructions

Tetra Whisper Internal Filter 10 To 30 Gallons,...
15,723 Reviews
Tetra Whisper Internal Filter 10 To 30 Gallons,...
  • UNIVERSAL DESIGN Tetra Whisper 20i Internal Filter is an all-in-one air pump and water filter system
  • INTERNAL FILTER Mounts on the inside of your aquarium with clip (included)
  • CATCHES DEBRIS Dense dual-sided mesh filters debris and fish waste
  • AERATES WATER Air-driven design filters up to 125 GPH while oxygenating water
  • CONVENIENT DESIGN Uses large easy to change Bio-Bag cartridges filter mounts inside aquarium making it possible to place...

Tetra Whisper internal filters are probably the cheapest in the market. It has four different sizes, and the largest one can filter up to 40 gallons. The best part is whatever size you buy; you’ll get that under $15.

It mounts on the aquarium with a clip or suction cup included in the package. Water flows from the top like a waterfall, which increases the air-water contact, and oxygenates the water. The operation of this filter is whisper quiet, as the name suggests.

There is no lid on the top, so the filter cartridge remains exposed. That helps in the maintenance; whenever you have clogged cartridges, use two fingers to lift them and replace or clean the filter element. You don’t need to put your whole arm down because the filter top is above the waterline.

Because it’s cheaper and for that, you have to sacrifice some of the features you would have liked. There is no option to adjust the flow; it runs on a preset flow rate. Also, small fish may get sucked in the motor housing, be careful about that. One easy solution is to use some fine mesh to cover the water intake.

If you want to buy a decent filter that is easy on the wallet and provides three-stage filtration, I suggest Tetra Whisper.

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Pros
  • A Cheap but effective internal filter
  • Provides basic three-stage Filtration
  • Whisper-quiet operation
  • Very convenient maintenance
  • Oxygenate the water well
  • Waterfall pattern flow output
Cons
  • Flow is not adjustable
  • Small fish can get sucked into the water intake

Sale
Penn-Plax Cascade 600 Fully Submersible Internal...
2,544 Reviews
Penn-Plax Cascade 600 Fully Submersible Internal...
  • QUIET & EFFICIENT: The Cascade 600 Submersible Filter quietly delivers crystal clear water throughout the aquarium. This...
  • ACCOMMODATING: The adjustable flow switch allows for increased or decreased water flow at will, which is extremely...
  • FULLY SUBMERSIBLE: The Cascade 600 utilizes 2 filter media chambers, and comes with filter media: 1 refillable Carbon...
  • VENTURI AERATION: The Cascade 600 features Venturi Aeration, which provides your tank with filtered, oxygenated water....
  • AERATING SPRAY BAR: In addition to the two Flow Nozzles and the Venturi Aeration, the Cascade 600 includes a Spray Bar...

Penn Plax cascade 600 submersible aquarium filter is suitable to use for both fresh and marine water. It is capable of filtering tanks up to 50 gallons. However, it could be overwhelming for the unit to clear up all the mess for a turtle tank.

It provides three-stage filtration and has two media chambers; one is for foam and the other one for activated carbon. Here, the foam filters particulate matter and also houses beneficial bacteria. The carbon cartridge removes toxins and harmful chemicals, tannins, and foul odor. A large-capacity media basket allows you to customize with the best filter media available on the market.

The outflow option is adjustable and directional; moreover, the spray bar option increases oxygenation and helps you to distribute the flow evenly in the tank. If you like to hide the filter or have a shallow water tank, you can also place the filter horizontally.

If you want to increase the oxygen level in your tank, you have the provision for connecting the air tube and air muffler to the flow nozzle. Due to the venturi effect, the air will mix with the water. So you don’t need an extra air pump Because you can get both functions from this single filter unit.

Although it’s powerful, it runs silently and is a good one to buy. Price is also reasonable considering the output you get. It’s effortless to install, but few complained that It’s not convenient to open it up for maintenance.

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Pros
  • 3-stage filtration
  • Customizable media chamber
  • Possible to place both vertically and horizontally
  • Adjustable flow
  • A spray bar distributes the flow evenly
  • No need for a separate air pump
Cons
  • Not the best suit for a turtle tank
  • Few found difficulties in maintenance

Sale
MarineLand Magnum Polishing Internal Canister...
2,792 Reviews
MarineLand Magnum Polishing Internal Canister...
  • INTERNAL CANISTER FILTER: Submerged motor for quick and easy startup.
  • VERSATILE FILTRATION: Two refillable chambers house carbon or customizable filter media.
  • MICRON WATER POLISHING: High-efficiency polishing with the micron cartridge (included).
  • FOR aquariumS UP TO 97 GALLONS: Capable of filtering 290 gallons of water per hour.
  • Included Components: Marineland Magnum Polishing Internal Canister Filer (Ml90770)

This is a canister-type internal aquarium filter made by Marineland. Marineland is well known for its quality products in the fishkeeping industry.

Along with three-stage filtration, it incorporates another pleated micron filter cartridge that provides crystal clear water. The exciting part is that you can also charge the cartridge with diatomaceous earth (Diatom) to increase the filtration efficiency further.

The main perk of this filter is you can customize and use your preferred media in a large dual chamber media house. In addition, it can filter as much as 97 gallons of water, which is the largest among all internal filters.

The efficiency you can expect is similar to a canister filter, which only sits inside the water instead of outside in a separate cabinet. It could be used in freshwater, saltwater, and turtle tanks where bioloads are higher, and a filter has to clean a lot of mess.

However, you should clean the filter sleeve or replace carbon monthly or as soon as it gets clogged. Few users mentioned that filter cartridges block too early, and you may need to clean or replace them every few weeks.

There are different opinions on how noisy the filter is. Some experienced noise over 5O DB and others found it extremely quiet. If something is pulled into the impeller, the noise may be created, so unplug it and check for any clogging or damage. You can seek assistance from their outstanding customer service if you have any problems.

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Pros
  • Three-stage filtration with additional polishing
  • Customizable media chamber
  • Diatom can be charged with the micron cartridge
  • Excellent customer care service
  • Suitable for all aquariums
  • High cleaning efficiency
Cons
  • With greater bioload, filter cartridges may got clogged early
  • Some users found it noisy

Benefits Of Internal Aquarium Filter

Power Outage

It remains submerged under the water. So, there is no need to prime the internal aquarium filter when power is restored after a power outage. 

However, other filters such as the HOB filter and canister filter may need priming to run the pump after a power failure. When you’re not at home, and if power failure interruptions occur, your aquarium filter may not work until you come back home and prime it. 

However, you don’t need to worry about that for the internal aquarium filter. 

Benefits of Internal Aquarium Filter
Benefits of Internal Aquarium Filter

Can Run In Low Water Level

Water evaporates continuously, and you need to fill the water regularly. However, if you were busy during the weekdays and couldn’t get enough time to do that, there is still no need to worry. The reason is an internal aquarium filter can work in low water levels. Some even can be installed horizontally. 

No Water Leakage

No external water leakage using internal filters. I have heard some tragic stories of aquarium filter leakage and flooding the house floor. However, internal filters are safe, and no such incidents are not possible. 

Can Easily Hide

You can easily hide an internal filter behind driftwood, plants, or any other decor so that it doesn’t hamper the aquarium aesthetic. 

Cheap But Effective

Internal aquarium filters are relatively cheap compared to other filters but still very effective. The operation cost is also low since it consumes less electricity than other aquarium filter types. Overall it’s a beginner-friendly filter; set up and use is very simple. 

Best Internal Aquarium Filter For Large Tanks

In larger tanks, internal filters are mostly kept as a backup option. However, some may still prefer the internal filter because of its effectiveness and cheap price. 

Suppose you want to use an internal filter in your large tank (more than 75 gallons). In that case, I suggest getting a Marineland Magnum Polishing filter. The reason is it has the provision to charge Diatomaceous Earth (Diatom) in the filter cartridge to augment the filtration capacity. 

Sale
MarineLand Magnum Polishing Internal Canister...
2,792 Reviews
MarineLand Magnum Polishing Internal Canister...
  • INTERNAL CANISTER FILTER: Submerged motor for quick and easy startup.
  • VERSATILE FILTRATION: Two refillable chambers house carbon or customizable filter media.
  • MICRON WATER POLISHING: High-efficiency polishing with the micron cartridge (included).
  • FOR aquariumS UP TO 97 GALLONS: Capable of filtering 290 gallons of water per hour.
  • Included Components: Marineland Magnum Polishing Internal Canister Filer (Ml90770)

See the video below on how you can increase the filtration efficiency of the Marineland filter using diatom. 

Wrapping Up

I hope the best internal aquarium filter list will help you to choose one for your tank. My overall choice is the Fluval Underwater U4 filter because it has some fantastic features, and it’s worth the money.

Fluval U4 Underwater Filter, Freshwater and...
6,710 Reviews
Fluval U4 Underwater Filter, Freshwater and...
  • Use as a primary filter for smaller aquariums, or supplementary filter for larger aquariums
  • Sleek design with easy grip water control panel and redesigned media cartridge to trap more debris
  • Convenient flip-top lid allows for quick and easy access to filter cartridge for maintenance or replacement
  • Position horizontally for shallow tanks, larger tanks with low water levels, or to create a decorative waterfall feature...
  • Designed for freshwater, saltwater and reptile environments up to 65 gallons

I have also added a video on how to use an internal filter effectively, which I feel could help you deal with any problems encountered during filter operation.

I want to hear your experience using internal filters and what filter you find best; please leave a comment below.

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