For large aquariums, the best aquarium filters

the best aquarium filters

Every freshwater and saltwater fish tank, regardless of size, requires an effective filtration system with sufficient biological and mechanical functionality to maintain the water clean and well-oxygenated.

Choosing the correct filter for a large aquarium is unquestionably difficult. In this post, we’ll show you how to select the best aquarium filter for large tanks and provide you product reviews of our top five filtration systems for large aquariums at Mr Review Expert.

What Do You Mean By “Large Tank”?

A large fish tank is often characterized as one that holds 75 gallons or more. The majority of large home aquariums are between 75 and 100 gallons, though you can obtain in-between sizes and, if you have space, a giant tank that contains 400 gallons or even more.

However, remember that the bigger the tank, the more influential the filtration system you’ll need, and that maintaining a large aquarium takes more time and effort than maintaining a smaller one. For smaller aquariums, check out our reviews of the Best 5 Gallon Aquarium Filter.

How Much Filtration Do Large Tanks Require?

The usual rule of thumb for filtration rates is that all of the water in your aquarium flows through your filtration system at least four times each hour. A minimum flow rate of at least 400 gallons per hour is required for a 100-gallon tank (GPH).

When purchasing a filter for my goldfish tank, I always choose one with a greater GPH rate than what I require. That extra flow guarantees that my fish have enough oxygen in the water, and the filtration equipment can handle the waste that unclean goldfish produce.

GPH Capacity

The GPH rate is highly dependent on the filter strength and type and the unit’s efficiency and condition. It’s fantastic to choose a greater GPH because it indicates your aquarium’s requirements will be better for your fish. You should, however, consider how the strength of the flow through the tank may affect your fish and plants.

Betta fish, for example, dislike excessive water movement and grow upset fast if they are unable to swim comfortably. One alternative is to use plants or decorations to buffer the flow or choose a filter machine with directional valves that you may alter to fit your needs.

Turnover Rate And GPH

The turnover rate differs from GPH. The turnover rate refers to the filtration unit’s and pump’s efficiency rather than the amount of water the system can cycle around the tank.

Dead Spots

If the filter’s GPH is insufficient for the tank’s size and environment, “dead spots” may develop. Dead spots are patches of water that are not disturbed by the water movement and typically arise when the filtration unit’s GPH is insufficient to evenly circulate all of the water in the aquarium.

The water in these dead patches is stale and stagnant, creating the ideal setting for hazardous bacteria that can impair your fish’s health.

I recommend using a filter with a larger GPH than the tank capacity allows to avoid dead areas. This is because the basic GPH does not account for the tank’s aquascape. The stronger the water movement must be to reach all aquarium sections, the more plants, rocks, driftwood, and other decorations you have.

The best technique to battle dead spots in large tanks is to utilize two filtration systems, on each end of the tank, to ensure that water is moved through the filter units in all tank sections.

Is Sand Captured In Large Filters?

Sand will not be sucked into a large filter unit under normal operating conditions. However, during ordinary tank maintenance, difficulties might emerge, and burrowing fish can create 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 company more frequently than you would otherwise. Sand, on the other hand, can harm the filter.

Filter is clogged

Suppose sand isn’t removed from the filter. In that case, it can clog it, allowing fish excrement, leftover food, and other debris to accumulate in the tank, where it will decompose and release dangerous ammonia into the water. Sand can block the biological media in some systems, reducing the efficiency of the microorganisms that process waste and cleanse the water.

Damage to the impeller

All filtration systems have a mechanical element that draws water up through the filter unit and the contained media before returning the clean, polished water to the tank through an impeller or motor. Sucking sand into the impeller might damage the filter’s working parts and prevent the impeller from rotating.

The filter will no longer remove water from the aquarium if the impeller stops operating. The only option is to completely replace the filter unit or submit it to the manufacturer for repair. As a result, several power filter manufacturers propose utilizing pebbles, gravel, or glass marbles as a substrate instead of sand.

Filter Parts Are Damaged

Even if the impeller is unaffected, and can still cause harm to the filter unit’s interior components by wearing down any plastic parts. As a result, the filter may not perform as well as it could. Tiny holes in the filter housing may form, producing leaks and preventing the unit from functioning correctly.

What to Look for in Large Tank Aquarium Filters

When selecting the right filtration system for large tanks, there are a few things to keep in mind. Your specific tank layout will determine the type of filter you select. However, there are a few general measures that all enthusiasts who keep big aquariums should bear in mind.

Appropriate Capacity 

As previously stated in this tutorial, selecting a filter with a suitable capacity for your fish tank is critical.

Examine the GPH on the product packaging and choose a filter with somewhat more capacity than you require for the size of your tank. If you have a large tank and plan to use two filters, choose units that are the exact GPH for your aquarium to avoid creating a too strong current for the tank’s inhabitants.

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

Stages of Filtration

Filtration in aquariums is made up of three parts:

  • Mechanical
  • Chemical
  • Biological

Each of these processes is critical for maintaining a healthy environment in which your fish may grow, and it’s critical that you understand how each part of the filtration system functions.


The act of removing particles of fish excrement, uneaten food, and general debris from the tank is known as the mechanical portion of the filtration system. A motor drives an impeller in the filter unit, which draws water up from the aquarium, through the filter medium, and back through the tank.

The filter media, which can be formed of foam, pads, floss, paper pleats, or diatomaceous earth, is used to capture and trap waste particles. Regularly clean the filter media by rinsing it in tank water to eliminate extra particles before it turns into sludge and clogs the filter. The mechanical filter will eventually become blocked if the filter media is not cleaned, and the water flow will be reduced.

If you don’t clean the mechanical filter at least once a month, it will accumulate enormous amounts of decaying debris, eventually overloading the biological filter and contaminating the water.


Toxins, heavy metals, and chemicals are extracted from the water when it travels through a chemical resin or media in the chemical filtering component of the system. Activated carbon has long been the preferred chemical filtration media, but you can also purchase devices that remove specific contaminants from water.

These media can be incorporated into the filter system to reduce the amount of maintenance required while also improving the water quality. However, you must still perform weekly partial water changes to keep nitrate levels to a minimum.

For the chemical filtering medium to be effective, it must be replaced regularly. Furthermore, because a chemical filter medium extracts some fish disease medications, you’ll need to remove that filtration system component while the fish are being treated. Remove the fish and place them in a specialized hospital tank with a filtration system that does not include the chemical element.


In a process known as the Oxygen Cycle, biological filtration uses several distinct kinds of bacteria to filter the harmful chemical byproducts formed by decomposing fish waste, leftover food, plant debris, and general detritus.

Ammonia is created in the first step of the Nitrogen Cycle. Ammonia is highly harmful to all aquarium occupants, and large quantities of the toxin can be lethal to your fish. Nitrosomonas bacteria convert ammonia to nitrites in the next step of the Nitrogen Cycle. If not eliminated, nitrates can be hazardous to aquarium life. Nitrites are turned to nitrates by another type of bacteria called Nitrobacter.

To survive, the bacteria that drive the Nitrogen Cycle require oxygen and a place to establish colonies. The natural part of a filter system comprises filter media that bacteria can thrive on within the unit. Because bacteria require oxygen to survive, the most effective biological filters expose the physical media to the air.

Filter Types

There are many types of filters, but canister and power filters are the best for usage in massive tanks.

Filters with a lot of power

Power filters come in various shapes and sizes, but they are all designed to hang on the rear of the tank. Most power filters combine all three forms of filtering, making them very efficient and straightforward to maintain. Power filters are sold as complete equipment with an integrated pump and filter cartridges that must be cleaned and replaced regularly to remain effective. Within the filter unit, all three steps of filtration are encapsulated.

Bio-wheels are included in many current power filters. A bio-wheel is a pleated material wheel that serves as a biological filter. The wheel spins while water is drawn over it by the pump, providing ample oxygen to the bacteria colonies on the surface.

Power filters are not recommended for thickly planted aquariums because they cause excessive surface agitation, which is incompatible with a CO2 injection system. A power filter can also create salt creep on the underside of the tank hood and the lighting unit when used in a saltwater tank. Furthermore, fish that are not powerful swimmers may become stressed if the flow in the tank is too high. Therefore a power filter may not be the ideal option in such a situation.

Filters in Canisters

Canister filters are normally kept in the cabinet beneath the tank. These pressurized devices carry out all three forms of filtration. Canister filters are available as a full unit with a built-in pump or a modular device with a separate pump. Modular units are advantageous because they can be integrated with other types of filtration, such as wet-dry units.

A U-tube is used to bring water into the device, and a spray bar is used to return the water to the tank. The water is drained from the aquarium into the canister filter unit. It passes through several chambers containing filter material before returning to the tank after the system is started.

Canister filters are an excellent choice for a large aquarium because they are powerful and efficient.


Regardless of the filter system you employ, regular maintenance is essential to keep everything running smoothly and properly.

Suppose your filter system uses cartridges to hold the filter media. In that case, you’ll need to replace them on a regular basis, and you’ll also need to wash the cartridges in tank water once a month to remove the sludge that would otherwise clog the device.

Make checking for bits of dirt stuck in the impeller housing and cleaning it a necessary part of your cleaning routine to ensure that the impeller is free and able to spin without impediment.

Considerations in Practice

There are a few practical issues to keep in mind when selecting a filter for a large tank:


The quantity of room you have both inside and outside the tank should be your first consideration. If you have a large aquarium in a space with little space around it, you don’t want a HOB (hang-on-back) filter that’s difficult to access for maintenance. As a result, a canister filter that fits beneath your tank is the superior option.


You want to be able to enjoy the tank’s inhabitants and your aquascaping efforts, not be distracted by the look of a large, black filter box, especially if you need two filter units to manage the environment effectively.

If that’s the case, you’ll need an external filtration system that won’t detract from your view.

Maintenance Effortless

You may not have the time to spend hours cleaning a sophisticated filter unit if you lead a hectic life. If that’s the case, go for a system that’s simple to manage.