Each freshwater and saltwater fish tank has to have an effective filtering system with enough biological and mechanical functionality to keep the water smooth and well-oxygenated, no matter its size.

It is certainly a challenge to choose the best filter for large tanks. We describe in this article how to choose the right aquarium filter for larger tanks and provide you with product reviews of our top five filtration systems that are perfect for a large setup.

Quick Comparisons of the Top 5 Aquarium Filters for Large Tanks

Product Features

Fluval 406 External FilterFluval 406 External Filter

Capacity: 100 Gallons
Flow Rate: 400 GPH
Dimensions: 9.5” L x 17.25” H x 7” W

Eheim Pro 4Eheim Pro 4

Capacity: 75 Gallons
Flow Rate: 280 GPH
Dimensions: 10” L x 10” W x 14” H

Fluval FX6 Canister FilterFluval FX6 Canister Filter

Capacity: 400 Gallons
Flow Rate: 1600 GPH
Dimensions: 10” L x 10” W x 21” H

AquaClear CycleGuard Power FilterAquaClear CycleGuard Power Filter

Capacity: 110 Gallons
Flow Rate: 400 GPH
Dimensions: 7.1” L x 13.9” W x 9.1” H

Penn Plax Cascade 1500 Elite Aquarium FilterPenn Plax Cascade 1500 Elite Aquarium Filter

Capacity: 200 Gallons
Flow Rate: 350 GPH
Dimensions: 11.5” x 20.5” x 12”

What Aquarist Consider Large Tanks?

Large Fish Tank

A large fish tank has a capacity of 75 gallons or more. Most large home aquariums are between 75 and 100 gallons in capacity, but you can get in-between sizes and, if you have the room, you can buy a huge tank that holds 400 gallons or more.

However, it is worth noting that the larger the tank, the more efficient the filtration system required, and maintaining a very large aquarium is more time-consuming and labor-intensive than maintaining a smaller setup. Check out our reviews of the Best 5 Gallon Aquarium Filter for Smaller Aquariums.

How Much Filtration Do Large Tanks Require?

So, how much filtration do large tanks require?

The general rule of thumb for filtration rates is that all of the water in your aquarium should be filtered at least four times per hour. As a result, a 100-gallon tank necessitates a flow rate of at least 400 gallons per hour (GPH).

When purchasing a filter for my goldfish tank, I always choose a unit with a slightly higher GPH rate than I want. The extra flow ensures that my fish have enough oxygen in the water, and the filtration unit can handle the amount of waste that dirty goldfish generate.

GPH Power.

The GPH rate varies greatly depending on the filter strength and form, as well as the performance and condition of the device. If you want a higher GPH, that is fantastic because it means that the conditions in your aquarium will be healthier for your fish. However, you should consider how the flow of water through the tank can affect your fish and plants.

Betta fish, for example, dislike excessive water movement and become agitated easily if they are unable to swim comfortably. One alternative is to buffer the flow with plants or decorations or to choose a filtration device with directional valves that you can customize to meet your needs.

Turnover Rate And GPH.

GPH is not the same as the turnover rate. The turnover rate describes the efficiency of the filtration device and its pump rather than the amount of water that can be circulated across the tank by the machine.

Dead Spots on Large Tanks.

If the filter’s GPH is insufficient for the size of the tank and its surroundings, “dead spots” will form. Dead spots are pools of water that are not agitated by the action of the water current and typically form when the GPH produced by the filter unit is insufficient to evenly circulate all of the water in the aquarium.

The water in these dead spots is stale and acidic, creating an ideal environment for harmful bacteria that can damage your fish’s health.

The main reason I recommend using a filter with a higher GPH than the tank capacity allows is to avoid dead spots. This is because the simple GPH does not account for the aquascape in the tank. Essentially, the higher the water current would be to enter all parts of the aquarium, the more plants, rocks, driftwood, and other decorations you have.

In large tanks, the best way to combat dead spots is to use two filtration systems, one at either end of the aquarium, to ensure that water is filtered into all areas of the tank.

Is Sand Captured in Large Filters?

Filter media

Sand will not be sucked into a massive filtration device under normal operating conditions. However, issues can occur during routine tank maintenance, and burrowing fish can cause sand clouds to billow around the tank, eventually ending up in the filter unit. Most of the time, sand in the filter only adds to your workload by requiring you to clean the machine more often than you would normally need to. Sand, on the other hand, will sometimes harm the filter.

Filter Obstruction.

If sand is not washed out of the filter, it can clog the unit, allowing fish waste, discarded food, and other debris to decompose and release harmful ammonia into the water. Sand can clog the biological media in some systems, reducing the efficiency of the bacteria that filter waste and purify the water.

Impeller Failure.

Both filtration systems have a mechanical element that uses an impeller or motor to draw water up through the filter unit and the enclosed media before returning the clean, polished water to the tank. Sand sucked into the impeller will damage the filter’s moving parts and prevent the impeller from turning.

When the impeller fails, the filter can no longer draw water from the aquarium. The only alternative is to install the whole filter unit or send it to the manufacturer for repair. As a result, many power filter manufacturers consider using pebbles, gravel, or glass marbles as a substrate rather than sand.

Filter Parts Damage.

Even if the impeller is unaffected, and will cause damage to the internal parts of the filtration device by wearing down some plastic components. As a consequence, the filter can not work as effectively as it should. Small holes can form in the filter housing, causing leaks and preventing the device from functioning properly.

What to Look for in Large Tank Aquarium Filters.

When it comes to selecting appropriate filtration systems for large tanks, they have their own set of specifications. The type of filter you choose will be determined by your specific tank setup. However, there are a few general considerations that apply to all large aquarium hobbyists.

Right Filter Capacity.

Check the GPH rating on the product packaging and choose a filter with slightly more capacity than you need for your tank size. If you have a very large tank and plan to use two filters, choose units that are the exact GPH for your aquarium so that you don’t generate a current that is too strong for the tank’s inhabitants.

Keep in mind that a tank with a lot of decoration and planting is more likely to develop pockets of stale water, especially in the corners. As a result, when purchasing your filter, make sure to keep this in mind.

Stages of Filtration

Filter Media

Mechanical, chemical, and biological filtration are the three components of aquarium filtration.
Each of these processes is essential for a safe environment in which your fish can survive, and you must understand how each component of the filtration process operates.

Filter Type

There are several different types of filters, but canister and power filters are the best designs for use in very large tanks.

Power Filters.

AquaClear CycleGuard Power Filter

Power filters come in a variety of styles, but they are all designed to stay on the back of the tank. Most power filters use all three methods of filtration and are extremely powerful and simple to maintain. Power filters are sold as complete units with an integrated pump and filter cartridges that must be cleaned and replaced regularly to remain reliable. The filter device contains all three phases of filtration.

Bio-wheels are used in many modern power filters. A bio-wheel is a pleated material wheel that serves as a biological filter. The wheel spins as water is drawn over it by the pump, supplying a steady supply of oxygen to the bacteria colonies on the surface.

Power filters are not the best option for a densely planted aquarium because they cause excessive surface agitation, which is incompatible with a CO2 injection system. A power filter can also cause salt creep on the underside of the tank hood and the lighting unit when used in a saltwater tank. Furthermore, fish that are not good swimmers may become agitated if the flow in the tank is too strong, so a power filter might not be the best option in this situation.

Canister Filters.

SunSun HW-304B 5-Stage External Canister Filter

Canister filters are usually housed under the tank in the cabinet. These are pressurized units capable of performing all three forms of filtration. Canister filters are available as a complete unit with an integrated pump or as a modular unit requiring a separate pump. Modular units are useful because they can be combined with other types of filtration, such as a wet-dry unit.

Canister filters usually include a U-tube to draw water into the device and a spray bar to return water to the tank. When you turn on the device, water is drawn from the aquarium and pumped into the canister filter unit, where it passes through various chambers containing filter media before being returned to the aquarium.

Canister filters are extremely powerful and reliable, making them an excellent option for a large aquarium.


Whatever type of filter system you use, some maintenance work will be needed to keep it running smoothly and efficiently.

If the filter system includes cartridges that house the filter media, they will need to be replaced regularly, and you will need to wash the cartridges in tank water once a month to remove the sludge that will otherwise clog the device.

To ensure that the impeller is free and able to spin freely, make it a part of your cleaning routine to search for bits of debris stuck in the impeller housing and clean it as required.


When selecting a filter for a large tank, there are a few practical considerations to keep in mind:


The first thing you can think about is how much room you have both inside and outside the tank. If you have a big aquarium that is in a small space, you don’t want a HOB (hang-on-back) filter that is difficult to access for maintenance. As a result, a canister filter that suits underneath your tank is the better option.


You want to be able to enjoy the tank’s inhabitants and your aquascaping efforts, not be distracted by the sight of a massive, black filter box, particularly if you need two filter units to handle the environment efficiently.

If that’s the case, you’ll need an external filter system that won’t obstruct your vision.

Ease Maintenance.

You may not have the time to spend hours cleaning a complex filter unit if you lead a busy life. If this is the case, choose a device that is simple and fast to manage.

Top 5 Best Aquarium Filters for Large Tanks.

Now that you know what filter to get for a big tank, let’s look at five of our favorite items that suit the bill.

1. Fluval 406 External Filter.

Fluval 406 External Filter


Capacity: 100 Gallons
Flow Rate: 400 GPH
Dimensions: 9.5” L x 17.25” H x 7” W.
Type: Canister.
Check Price

Fluval is a well-established business whose goods are typical of high quality and dependability.

The Fluval 406 External Filter includes an instruction manual and is simple to use. It’s quick and easy to get water flowing through the filter thanks to the self-primer, and the noise reduction technology used in the design means that the pump is much quieter than many of the product’s rivals. The interchangeable filter baskets and easy-lift clamps make machine maintenance a breeze.

The only real disadvantage of the filter unit is that it does not come with much filter media or hose length.

Fluval 406 External Filter Pros & Cons
  • Well-made and long-lasting.
  • The process is very quiet.
  • The process of priming oneself.
  • More filter media and hose could be used.

2. Eheim Pro 4.

Eheim Pro 4

Capacity: 75 Gallons
Flow Rate: 280 GPH
Dimensions: 10” L x 10” W x 14” H
Type: Canister.
Check Price

I use Eheim filters in both of my tanks because I appreciate their quick, easy-to-clean nature and dependability.

This external canister filter has a push pump button to start the siphon operation, and the flow can be adjusted from zero to full-on, which is a useful feature if you have fish that don’t like too much current in the tank. The media trays are designed to be lifted out individually for washing, and each tray has a triangular marker in one corner to ensure proper alignment when replacing them in the unit.

There is a push-button release that allows the outlet and intake valve block to be disconnected from the unit for cleaning, making the process easy and fast to complete.

Eheim Pro 4 Pros & Cons
  • A style that is easy to use.
  • The process is very quiet.
  • The process of priming oneself.
  • The flow rate can be changed.
  • The construction is not solid.

3. Fluval FX6 Canister Filter.

Fluval FX6 Canister FilterCapacity: 400 Gallons
Flow Rate: 1600 GPH
Dimensions: 10” L x 10” W x 21” H
Type: Canister

Check Price

The Fluval FX6 external canister filter might be just what you need if you need a 400-gallon aquarium filter.

The filter has an extendable intake tube that allows you to adapt it to most tank sizes and shapes. The pump is self-priming; just plug it in and you’re ready to go. Every 12 hours, a special air evacuation function eliminates air bubbles from the system, ensuring that the full vacuum is still preserved.

Mechanical, biological, and chemical filtration is used in the device, and the unit comes pre-loaded with a complete range of filter media that can be interchanged and modified to suit your setup. The purge valve mechanism simplifies maintenance.

Fluval FX6 Canister Filter Pros & Cons
  • A style that is easy to use.
  • Filter media that can be customized.
  • The process of priming oneself.
  • Sponge filter media must be replaced on a regular basis.
  • The style is bulky.

4. AquaClear CycleGuard Power Filter.

AquaClear CycleGuard Power Filter

Capacity: 110 Gallons
Flow Rate: 400 GPH
Dimensions: 7.1” L x 13.9” W x 9.1” H
Type: Canister

Check Price

The AquaClear CycleGuard Power Filter is a HOB device that uses multi-stage filtration to keep large tanks’ water quality high. The device uses throwaway filter cartridges for mechanical, biological, and chemical filtration, and it comes with a complete set of filter media to get you started.

This filtration device has a gentle waterfall design that returns clean water to the tank without causing an undue surface disturbance, making it an excellent choice for fish and plants that dislike strong currents in their environment. The design also ensures that the water is well oxygenated.

AquaClear CycleGuard Power Filter Pros & Cons
  • Design of a gentle waterfall return.
  • The filter media is included.
  • Filtration in three stages.
  • Filter cartridges are costly to repair.

5. Penn Plax Cascade 1500 Elite Aquarium Filter.

Penn Plax Cascade 1500 Elite Aquarium Filter


Capacity: 200 Gallons
Flow Rate: 350 GPH
Dimensions: 11.5” x 20.5” x 12”
Type: Canister

Check Price

One of the best 200-gallon fish tank filter systems available is the Penn-Plax external canister filter. The device includes everything you need to attach it to your aquarium. The unit has fully adjustable, 360-degree rotating valve taps for adjusting and redirecting the flow to fit your configuration, and it starts with a push-button primer.

The filter system comes with large filter trays, input/output tubing, and filter media to get you started, but you can configure the media to meet your needs. Because of the extra-large filter trays, you can use more filter media, which needs less regular replacement. The pump is extremely quiet and effective.

Penn Plax Cascade 1500 Elite Aquarium Filter Pros & Cons
  • Trays for filter media that are extra-large.
  • Filtration that can be tailored to your needs.
  • Flow is fully adjustable.
  • It’s expensive.
  • There is an excessive amount of water bypassing around the filter compartments.

6. AquaClear 70-Gallon Biomax Filter.

AquaClear 70-Gallon Biomax Filter

Type: Biological
Material: Porous Inorganic Compound
Filter: AquaClear 70-Gallon Biomax HOB Filter only.

Check Price

If your choice in biofiltration is the easiest one of our rated AquaClear filters, these branded filter inserts may be the perfect choice for your tank! Contrary to others, biofiltration is considered to be the AquaClear HOB. This media comes in a mesh jar, so it’s only going to be popped into your filter!

This insert fits into the top of your filter above the sponge of water polishing and gets full oxygen exposure. The Aquaclear design does not allow the flow of water around, or bypass, the bio-mediate level, even if it may be awkward in other HOBs. The inorganic noodle composite makes a lot of bacterial growth surface area.

AquaClear suggests that every three months bio-media be replaced, thus reducing the effectiveness of biofiltration dramatically and causing harmful ammonia spikes. Frankly, I don’t know that. I substitute this medium only if the mesh bag or particles begin to break down. It worked without problems with a monthly rinsing in aquarium water, but this is one of these personal calls.

AquaClear 70-Gallon Biomax Filter Pros & Cons
  • No hassle, toss in the filter end!
  • AquaClear HOB Filter Ideal Kind of bio-media.
  • In pre-filled mesh bags, longer-lasting media are available.
  • After 3 months the manufacturer suggests substitution.
  • It suits only labeled filters and is not suitable for other HOBs, but can be used in canister filters.
  • Price choice if reimbursed as prescribed every 3 months.

Final Thoughts.

We hope you find this guide and product reviews to be useful.

The AquaClear CycleGuard Power Filter is our favorite of the items we looked at. This substance is powerful enough to clean a large tank, but the gentle waterfall return ensures that fish and plants are not tossed around by a strong flow. The three-stage filtration system includes everything you need to provide your fish with a healthy atmosphere. Furthermore, the HOB nature of this high-quality external filter is perfect if you do not want an unsightly device in your tank but do not have an aquarium cabinet in which to conceal a canister filter system.

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