install aquarium filters

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.  Althought setting up an aquarium filter is not hard, 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.

1. Air powered aquarium filters

Air-powered internal filters are the most basic of all aquarium filters.  They’re frequently used on small “nano” and desktop aquariums.

This type of filter is perfect for aquariums that 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.

The most common design for air powered filters is to be placed at the bottom of your tank.  However, some designs allow them to be attached to the side of your fish tank with suction cups.  In either case, the filter should be installed below the water level.  This is because the air bubbles need to rise to draw water through the filter media.

Some aquarium keepers like to use this type of filter in addition to a power filter.  Installing two types of filtration allows you to have a backup incase the main filter malfunctions.

Last update on 2024-05-24 / Affiliate links / Images from Amazon Product Advertising API

Last update on 2024-05-24 / Affiliate links / Images from Amazon Product Advertising API

TIP: Be careful to position the filter so the rising bubbles don’t get sucked into the power filter’s intake tube.

Installing the filter too close to the power filter may cause the power filter to gurgle because the bubbles are getting caught in the pump mechanism.  This 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. What is a check valve? This tiny gadget is a one-way valve that lets air pass through it in one direction, but will stop water from back siphoning and going the other way.  They are installed in the tubing from the pump to the tank and are a must have!  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.

These valves always have a "right way" to install them.  Check valves are directional, so make sure you install it as directed on the package.  Many times there will be an arrow on the side to show you which direction the air is allowed to go.  The arrow should be pointed towards your tank and away from your pump.

We recommend this valve that you can find on Amazon.

There is no one size fits all answer for the best spot to place your air powered filter.  The perfect location will depend on the size and shape of your aquarium, your fish tank's decorations, and even the type of fish you keep.  One of the benefits of these filters is how easy they are to move.  So, experiment with a few locations to see what works best for your underwater world.  You might want to consider starting with a location that is more central in your fish tank and not directly next to a large decoration.

You can also check out this video showing how to install an air powered filter.

2. Undergravel filters

The undergravel filter (UGF) is another air-powered filter option.  However, this type of filter is placed under the gravel or substrate.  Under gravel filters are great for keeping the filter's components out of sight and also to help stimulate beneficial bacteria to grow in the gravel.

Although there are situations where this type of filter is a great option, setting it up incorrectly or using it in the wrong fish tank can actually cause more harm than good.  Because of there, there are some important considerations to keep in mind.

The first thing to consider is that these filters are not the strongest options out there.  In many cases, they are best used as sidekicks rather than solo heroes.  So, for larger tanks it would be best to choose another filter option or plan on using the UGF as a second filter in your fish tank.

Let's take a look at how the filter works.  Understanding what is happening will help ensure you set it up correctly.

Undergravel filters are made up of plastic plates that are placed at the bottom of your fish tank.  These plates are perforated and should cover your aquarium's entire base.  Attached to these plates are "uplift tubes".  These tubes allow the water to flow through the gravel, under the plate, then pushed out at the top of the tubes to start the cycle over again.  This water flow is great for helping good bacteria grow which turns your gravel bed into a biological filter.  What powers this water flow will depend on your specific filter.  Many smaller undergravel filters are powered by air pumps attached to an air stone.  However, some filters can be powered by larger water pumps which can create a stronger water flow.

To install this type of filter, your fish tank must not have any substrate or decorations.  It is easiest to set them up in a new aquarium.  After covering the entire bottom with your plates, connect your uplift tubes and place your substrate on top of the plates.  Make sure you use a large enough substrate, such as gravel, to prevent it from falling through the gaps in your plates.  After filling your tank with water, connect your pumps and enjoy your new filter.  If you are using air pumps with an air stone diffuser, you will enjoy an added benefit.  The air bubbles not only create the uplift, but also aerate the water.

In reality, the UGF functions primarily as a
biological filter that helps break down debris.

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One downside to undergravel filters is the difficulty of cleaning them.  Over time, small pieces of debris can collect under the plates and lead to issues such as higher levels of ammonia.  To help prevent this, you’ll have to regularly use a gravel siphon to keep the gravel bed clean. This siphon is a good option.  If neglected, debris and algae can build up in the gravel and the UGF won’t function efficiently.  To make matters worse, the accumulated sludge will eventually decay and release even more algae-promoting nutrients back into the aquarium water.

For a higher water flow, 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.  Alternatively, you can opt for a water pump instead.

Due to these challenges, and the fact that other options are easier to clean and maintain, many aquarists choose to use a power filter or canister filter for better filtering capacity. More on canister filters later.

3. Hang-on-the back (HOB) power filters

Hang-on-the-back or HOB power filters are one of the most popular categories of aquarium filter systems.  These filters are, as the name implies, designed to hang on the back rim of the aquarium.  HOB filters come in a range of sizes designed to work for tanks from 5 gallons up to several hundred gallons.  There are even 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.

One of the benefits of HOB filters is the ability to use multiple types of filtration materials - from activated carbon to mechanical filtration for particulate removal.

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Water is drawn from the aquarium and pumped into the filter box.  The aquarium water then 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.

4. Internal power filters

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.

Preview Product Rating Price
Aqueon Quietflow Internal Power Filter, 40 Gallon, Aqueon Quietflow Internal Power Filter, 40 Gallon, No ratings yet $37.55Amazon Prime

Last update on 2024-05-24 / Affiliate links / Images from Amazon Product Advertising API

5. Canister filters

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.

Setting up a canister filter takes a little planning.

Last update on 2024-05-24 / Affiliate links / Images from Amazon Product Advertising API

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 hose is too long, it can collapse and kink under the weight of the water inside. But if the hose is too short, it will be difficult to remove the filter for maintenance.

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.

Aquarium Filter Setup: Guide to Proper Installation