Best Aquarium Filters For Large Tanks

If you’ve got a large tank, chances are you’re either keeping big fish or your tank is fully stocked with a lot of tropicals.
No matter what kind of aquatic life is in your big aquarium, you’re going to need one of the best filter system to keep a large fish tank clean and healthy, and the bigger your aquarium is the better the filter need to perform.
So it is in your (and your fish) interest to pick the best aquarium filter that is able to cope with large tanks.

We set up large tanks for many reasons.
Maybe we want a wall-to-wall aquatic world in the office to impress clients.
Kids (and adults) really enjoy a relaxing aquarium when waiting for the dentist.
Fans of “monster fish” need all the space they can get to house big cichlids and other “tank buster” species.
Sometimes we need extra space when keeping gentle schooling fish like discus.
Perhaps all you want is a big aquarium packed with tiny tropical fish and life plants.
The obvious difference between small and large aquariums is their physical dimensions.

Big aquariums are longer, wider and deeper.

They need more light to illuminate the tank, higher wattage heaters to keep the water temperature stable and more powerful filtration to maintain good water quality.
Under-sizing the lighting system creates a dim aquarium.
Skimping on heater wattage results in fluctuating water temperature.

It’s the same with filtration.
Just like with small tanks, big tanks require proper filtration to keep the water crystal clear, free of dissolved organics and suspended particles.
But a filter that works on a 20 or 30 gallon aquarium won’t work on a 55 gallon or larger tank.
Keep reading and to find out the reasons.

Large tanks come in a variety of shapes.
They can be very tall, long, deep or a combination of all three.
You may have even seen cylindrical and cube-shaped tanks.
No matter the shape, large tanks are especially subject to the physics of settling: as particles of debris, fish waste, uneaten food, dead algae cells, plant fragments and fish slime glide through the water they eventually slow down and settle at the bottom of the aquarium.

This organic matter eventually forms a sludge layer in the gravel bed.
Live and plastic plants, ornaments and rocks slow water flow and aid in the particle settling process.
If left unchecked, the organic matter decomposes, consuming oxygen and releases algae-promoting nutrients into the water.

High organics and increased fish disease organisms go hand-in-hand, so limiting organic build-up reduces the incidence of disease in the aquarium.
To overcome the tendency of debris to settle and form sludge, the water must be “agitated” enough to resuspend the particles.

In smaller tanks this is accomplished with internal and hang-on-the-back power filters.
But big tanks need to move larger volumes of water to stir up the entire depth and length of the entire tank.
You might think that adding a large powerhead will solve the problem.
But resuspending the particles of debris will just create hazy, cloudy water.
The water must be filtered to remove the debris from the aquarium.

We know that water movement alone is not true “filtration.” The debris needs to be removed from the aquarium water.

This is accomplished by pairing a powerful water pump with a large container of filter media .
This is the idea behind the canister filter.
You may wonder why filter manufacturers don’t simply put larger pumps on hang-on-the-back (HOB) filters.
HOB filters use disposable filter cartridges to capture debris and provide some chemical filtration with activated carbon.

The cartridge material is designed to capture fine particles and still pass water through the filter cartridge.
As the cartridge clogs, water backs up behind the cartridge.
Pumping a lot of water through a cartridge results in rapid clogging and poor filter efficiency.
Cartridges just can’t handle the high flow rate.

A tall canister filled with mechanical filtration media made of sponge, ceramic beads and rings, allows for a higher flow rate and efficient solids removal with the clogging problems found with cartridge filters.
Canister filters will capture debris while allowing for a high volume of water to be circulated in the aquarium.
The higher flow rate is essential for flushing the tank and circulating oxygenated water through the entire aquarium.
But canister filters do more than capture debris.

The large size of the canister allows for the use of additional filtration materials.
The mechanical filtration materials capture debris, protecting the chemical and biological filtration media from becoming clogged.

This means you can add a second stage of filtration by adding activated carbon to the canister.
Granular or pelleted activated carbon will adsorb yellow discoloration caused by organics, odors and other organic substances that build up in aquarium water.

The second stage can include specialty filter media like granular phosphate-removers to reduce algae growth.
You also have the option to add biological filtration media as a third stage of filtration.

Biological filter media act as a supplemental surface area for the growth of beneficial bacteria, in addition to the many suitable attachment surfaces inside your aquarium.
To learn more about the filtration systems, check out this article.

Canister filters are rated for specific aquarium sizes by the filter manufacturer.
This usually based on how many times the filter will process the entire aquarium water volume every hour.
This “turnover” rate philosophy varies from country to country and filter manufacturer.
Some aquarists are satisfied with a low turnover of rate of once an hour while others prefer up to three times per hour.
There is no official rule on what the turnover rate should be.
In general terms, larger fish make a lot of solid waste.
The larger particles are highly visible and detract from the tank’s appearance.
A higher flow and turnover rate is often selected when keeping big fish or with a densely stocked aquarium.

Canister filter flow rates are usually stated for an empty canister filter (no flow obstruction) with zero head pressure.
In other words, the flow rate is calculated in the best possible conditions but does not reflect real-world use.
Look for a flow chart based on “head” or pumping height.

The water must be pushed up the tubing to reach the top of the aquarium.
The head flow rate will be significantly less than the maximum flow rate used for advertising purposes.
You may discover that you will need to choose the next larger filter size to reach the desired flow rate for your aquarium.

Some canister filters come with quick disconnect valves, making it easy to disconnect the filter from the hoses without disassembling the entre hose system.
Quick disconnects make it much easier to service the filter and change filter media.
Be sure to compare the intake and outlet design.
Some filters provide basic tubing while other include a directional outlet nozzle, aeration device and a solid mounting system to hold the tubing in place.

Hydor Professional series canister filters are available in several sizes for aquarium up to 150 gallons.
The canister uses square media baskets that use pre-cut sponge and fine particulate polishing pads.
The baskets stack easily and can be filled with activated carbon and bio-filter media.
The pump uses a ceramic impeller shaft for vibration-free operation.
Quick disconnect valves make maintenance easy.
The intake has a telescoping feature that adjusts the depth of the intake screen.
The Hydor Professional series filters include a START button that is a manual priming pump.
A few presses of the button starts the siphon, filling the canister with water.
The filter kit includes thick-walled non-kinking hoses, filtration materials and a spray bar outlet to aerate the water.

The Fluval FX6 canister filter is a large, heavy-duty canister filter rated for aquariums up to 400 gallons.
The stacking media baskets hold up to 1.5 gallons (volume) of filter media.
Using a “basket in a basket” design, media baskets nest on top and inside of one another.
This allows for a large amount and variety of filtration media to be used but keeps the canister compact in size.
The FX6 is 21-inches tall and fits under most large aquarium stands.
The water pump is built into the side of the canister instead of the top like other canister filters.
The electronic pump motor automatically senses the flow rate and compensates for filter clogging by speeding up the pump.
The motor also stops briefly every 24 hours to allows entraped air to purge from the canister.
This ensure no air pockets form inside the filter.
Large intake and return tubing connect to high-quality quick-disconnect valves for easy filter change-outs.
The twin outlet nozzle lets you split the power outflow in two directions inside the aquarium.

The Polar Aurora canister filter, rated for aquariums up to 200 gallons, combines mechanical (2), chemical, biological and ultraviolet disinfection for five stages of filtration and water treatment.
The canister contains four media baskets to hold a sponge filter pad, fine white particulate filter pads, activated carbon, ceramic rings and plastic bio-balls.
All this media is included with the filter.
The canister has a priming button that starts the siphon, making start-up easy.
A quick-disconnect valve block separates the tubing from the canister as a single unit.
Tubing length is five feet and includes a spray bar for aeration. The 9-watt UV light will kill bacteria, parasites and fungi pathogens as well as algae.

The Forza series of canister filters are rated for aquariums up to 175 gallons.
The canister contains four media baskets designed to hold pre-cut coarse and fine particulate filter pads.
A sealed activated carbon cartridge drops into one of the baskets.
Ceramic rings and plastic bio-balls are included with the filter.
The color-coded inlet and outlet connections are incorporated into a removable valve body for easy maintenance.
A priming pump button starts the siphon to fill the canister.
The lid of the canister includes a fold-away handle that makes it easy to carry the filter to the sink for cleaning.
The Forza canister filters come with basic inlet and outlet pipes including a spray bar for aeration.

Built around the standard Forza canister filter range, these advanced models include a 13-watt ultraviolet bulb.
The UV bulb is positioned inside the canister, taking up less space under the aquarium than free-standing add-on UV disinfection units.
The powerful 13-watt bulb provides extra-strong microbe-killing power.
In order for aquarium UV bulbs to be effective, the radiation must pass through the water and strike the microorganisms.
The higher-wattage UV bulb inside the Forza canister filter will have a better “kill rate” than low-wattage UV bulbs.
This means less algae problems and inhibition of disease-causing bacteria, parasites and fungi.
The UV series of canister filters include four media baskets designed to hold pre-cut coarse filter and fine particulate filter pads.
A sealed activated carbon cartridge drops into one of the baskets.
Ceramic rings and plastic bio-balls are included with the filter.
There is also an automatic shut-off switch for the UV bulb.
If the canister is tilted more than 30 degrees, the light is automatically turned off to prevent over-heating.

Our best pick is the Hydor Professional Canister Filter Line.
It combines reliability, effectiveness and value.
This makes the Hydro professional filters our top choice for the average large aquarium owner.
The canister holds plenty of filter media, runs quietly and has a reliable track record.
Maintenance is easy.
The filter baskets can be filled with the media of your choice or original Hydro media.
Hydor makes an in line UV unit that attaches to the return tubing if you want to add a UV later.

The Fluval FX6 Filter is designed to process a large volume of water and pass it through dense layers of filtration media.
The addition of “smart-filter” technology and increased water flow capacity pushes this filter up to the extra large aquarium filter category.
The high capacity canister, heavy-duty construction and high-tech water pump increases performance and price, making the FX6 the runner up in the larger canister filter category.