Aquarium Filter Setup: Guide to Proper Installation

How to install and run an aquarium filter is one of the most frequent questions most aquarists ask.
Setting up an aquarium filter is not hard but it always helps to know a few insider tips to make the process go smoothly.

No matter if you’re setting a filter in the aquarium for the first time or upgrading to a more advanced filter, we’ll help you make the installation and set up go as smooth as possible.
We have picked the 5 most common aquarium filter types and we provide the tips you need for a successful installation.
You can skip directly to the filter you have or just read them all to have a more thorough understanding on how the set up of aquarium filters work.

Air-powered internal filters are the most basic of all aquarium filters.
They’re frequently used on small “nano” and desktop aquariums.
Some aquariums are too small to handle the flow rate of a hang-on-the-back (HOB) power filter or aren’t designed to accommodate an external filter.
Air-powered aquarium filters use an air pump to drive the filter.
As air bubbles rise in a lift tube, water is drawn through the base of the filter and through the filter media.
The filter can be as simple as a sponge that captures debris.
Some filters are designed to stick onto the side of the tank with suction cups.
In either case, the filter should be installed below the water level.
The air bubbles need to rise to draw water through the filter media.
Some aquarists like to use this type of filter in addition to a power filter.
It works as a backup incase the main filter malfunctions.

This may cause the power filter to gurgle because the bubbles are getting caught in the pump mechanism.
It could even cause the power filter to lose its prime and damage the impeller.
Any time you use an air pump it is important to install a check valve.
A check valve is a one-way valve that lets air pass through but will stop water from back siphoning in case of a power failure.
If the air pump accidentally gets unplugged or there is a power failure, water can flow down the airline, draining the aquarium, ruining the air pump and flooding your home.
Check valves are directional, so make sure you install it as directed on the package.
We recommend this valve that you can find on Amazon.
Check also out this video showing how to install an air powered filter.

The undergravel filter (UGF) is an air-powered filter that uses the same uplift principal.
A perforated plate is placed in the empty aquarium, then covered with aquarium gravel.
Uplift tubes, each with a porous air diffuser, are connected to the plate.
Once the aquarium is filled with water, an air pump is connected to the air diffusers, creating a steady stream of rising bubbles inside the tubes.
This cause a lift effect, pulling aquarium water into the gravel bed and out of the top of the uplift tubes.
This aerates the water and creates water circulation inside the aquarium.
The idea behind the undergravel filter was to stimulate beneficial bacteria to grow in the gravel.

You’ll have to use a gravel siphon to keep the gravel bed clean. This siphon is a good option from Amazon.
If the gravel gets plugged the UGF won’t function efficiently.
The accumulated sludge will eventually decay and release algae-promoting nutrients back into the aquarium water.
You’ll need a large air pump to drive the air stones.
Be sure to use check valves or mount the air pump above the aquarium to avoid water backflow problems.
Most aquarists choose to use a power filter or canister filter for better filtering capacity and easier maintenance. More on canister filters later.

Hang-on-the-back or HOB power filters are one of the most popular category of aquarium filter systems.

Designed to hang on the back rim of the aquarium, HOB filters come in a range of sizes suitable for tanks from 5 gallons up to several hundred gallons.
There are even a micro HOB filters designed for nano tanks.
While designs vary the principal is the same.
HOB filters place the filtration hardware outside of the aquarium.
This frees up valuable tank space for fish, inverts, plants and live rock.

Water is drawn from the aquarium and pumped into the filter box.
The aquarium water flows by gravity through the filter materials (usually a slip-in cartridge) and back into the tank.

HOB filters take up space behind the aquarium.
Make sure you have enough room behind your tank to accommodate the filter. You may have to move the tank and stand away from the wall if the HOB filter is too large.
If your aquarium has a traditional lid or light canopy, you’ll probably have to cut out a section of the plastic frame to make room for the filter.
Some canopies already have cut outs molded into the plastic.
Score the edges of the cut out with a box knife and it will easily snap off.

If you have an open top aquarium, you can hang the filter anyplace on the back or side of the tank.
Since the pump is constantly filling, it’s important to adjust the level of the filter box to make sure it is not tipping backwards.
Most HOB filters have a leveling screw or tab that lets you adjust the “tilt” of the filter.
If the HOB filter is tilted away from the aquarium water could splash out of the filter and drip behind the aquarium.
That’s another reason to keep the filter cartridge clean.
If the filter gets slimy and clogged, water will “back up” behind the cartridge, potentially causing a spill.
Be sure to use a drip-loop on the power cord.
Water likes to flow downhill and if it finds its way to the power cord, it will follow the cord all the way to the electrical outlet.
This can cause a short circuit and has caused fires.
A drip loop prevents the water from getting into the electrical outlet.
Instructions for proper routing of the power cord are illustrated in the filter’s instruction manual.

HOB power filters normally require priming before plugging in the power cord.
The water pump inside the filter can’t suck in water because there is air surrounding the pump impeller.
Fill the filter box with aquarium water then plug it in.

It is important to completely fill the aquarium with water before starting the pump.
It will make the initial priming of the pump easier.
You’ll hear a lot of gurgling and wooshing noise as the pump pushes out air and begins to pull in water.
If the filter won’t pump water, check that the uplift tube is properly seated over the impeller.
If the tube is not seated right, the pump won’t be able to pull in water.

New HOB filters may take up to 24 hours to “break in” and quiet down.
You’ll occasionally hear the filter make noise as the spinning impeller seats itself.
There may also be some slight vibration that will eventually fade after a few hours.
You may want to check out this video as well.

An internal power filter is like the HOB filter but it is designed to be fully submersible.
The motor, filter box and filter cartridge are submerged in the aquarium.
Water recirculates through the filter cartridge and back into the tank.
Internal power filters range in size from tiny for nano aquariums up to tanks around 30 gallons.
The filters attach to the aquarium by suction cups or a clip that hangs on the side of the tank. Some internal filters have an adjustable aeration valve.
The water pump pulls in air and sends it out of the pump nozzle. You can control the amount of bubbles with a tiny adjustment valve.
Too much air can create a gurgle noise. Keep in mind that the rising bubbles will break at the water surface, creating a steady mist.
Some aquarists aim the outflow across the length of the aquarium to minimize the chances of mist making the edge of the aquarium damp.

Canister take water filtration to a higher level by using multiple stages of mechanical, chemical and biological filtration.

The basic design is the same with most canister filters.
Water flows by gravity into the canister and filter media.
Filter media options vary by brand but all canisters are designed to hold a variety of filter media. Pre-cut sponge filter pads capture debris as water flows into the canister.
This reduces clogging and coating of other media in the filter.
Next pre cut activated carbon pads or bags of carbon provide chemical filtration to remove water-degrading organics, odors and colors.
You can also use your favorite specialty media like phosphate-remover for algae control.
As a final stage you can add biological filter media for ammonia and nitrite removal.
A water pump is built into the canister, usually at the top of the canister tank.
The pump takes the purified water and pumps it back into the aquarium.

Most aquarists place the filter under the aquarium, in the cabinet.
To service the filter, you’ll have to remove it from the cabinet and carry it to the sink.

Fortunately, many canister filters include quick disconnect valves, making it easy to disconnect the filter from the hoses without making a wet mess.

Speaking of hoses, this is where planning is important.
Your canister filter will have an inlet and return hose.
The inlet hose brings water to the canister filter by gravity.
Filtered water is pumped through the return hose, back to the tank.
The filter will include an intake pipe and screen.
A curved ridged pipe and nozzle are used on the return side.
The hard-plastic pipes prevent the hoses from kinking at the top of the aquarium.
You’ll have extra hose that can be trimmed for a neat appearance.

If the filter comes with quick-disconnect valves it is easier to use shorter hoses.
If no valves are included, leave enough hose so you can move the canister out of the aquarium stand.
Otherwise you’ll be removing the canister lid from the canister, under the aquarium.
Water drips are impossible to prevent.
Spilled water will soak into the aquarium cabinet, damaging the wood and potentially causing an electrical problem.

We hope you find these tips on how to set up the various types of aquarium filters helpful. Following few hints can make your life much easier and get you through the process quicker and safer.
Let us know how your set up goes.
We would love to hear from you in the comments.