Aquarium Air Pump (& Air Stone) Placement Guide

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Aquarium air pump, if you have got them for the first or even if you already have it. A question that may come to your mind is, where should an aquarium air pump be placed?

The pump itself (the mechanical part) is placed outside the aquarium, the part that is submerged is the tube and whatever is fitted in its outlet (porous stone, sponge filter, etc.). The best place to position the mechanical part of the pump is above the surface of the aquarium water level, due to safety in case of malfunction.

What Is An Air Pump For Aquarium?


The air pump is a kind of pump, that generates a flow of air bubbles through a tube, causing the water in the aquarium to move to the surface. Thus, preventing the formation of stagnant areas and facilitating gas exchange with the external environment.

These gases are (mainly) oxygen, nitrogen, and carbon dioxide. It has the function of moving the water column, allowing greater exchange of gases between the aquarium water and the atmosphere.

However, it is not capable of removing impurities from the water or, transforming ammonia into nitrites and nitrates.

In addition to its complementary use to maintain good health in the tank, this type of pump is also used for ornamental purposes, creating effects and bubble curtains.

It is very easy to understand why to inject air into the system, its advantage is simply to cause a disturbance in the water, thus breaking the surface tension, which (due to osmosis) promotes gas exchange, leading to CO² molecules (and other various gases present in our aquariums) to the outside, and the O² (and other atmospheric gases) into the tank. This will promote beneficial gas renewal to the system.

In addition, the physical movement of air bubbles within the water column will “pull” along the water, creating a certain “current” and causing a constant flow of water inside the aquarium, where all the areas will receive renewed water through the gas exchanges promoted on the surface.

Read Also: Do Bettas Need Air Pump?

Can Air Pump Go Below Tank?

Positioning the pump above the water level prevents that in the event of a power outage, or malfunction (failure or tube clogging), the water returns through the air tube, due to gravity and capillarity, which will likely damage your equipment, in addition to the risk of drain out the water of your tank, which is not good, potentially causing damage.

If positioned below the water level and a failure occurs, the tendency is for the pressure to return by gravity into the pipe and, consequently, into the pump (which will likely cause irreparable damage).

Sometimes the aquarist with limited space has to place his pump somewhere below the water level of the aquarium, when this occurs, in order to protect the system and equipment, we can make use of a valve called “check valve“.

Read: Complete Air Pump, Air Stone, & Sponge Filter Setup Guide

What Is A Check Valve And Is It Necessary?

It is a type of valve that works with fluids. Within a failure in the pump or the detachment of the tube, the water pressure can cause a siphon action, just similar to how you perform a water change.

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The non-return valve is an indispensable safety item for your aquarium air system as it prevents water from returning through the hose and entering the air compressor.

An example is when there is a power outage and the aquarium water ends up coming back through the hose and without this valve it enters the air outlet, flooding all the equipment, which can cause a serious accident in your house.

You can watch this video from Trafish Aquatics YouTube Channel to know about check valves – how they work.

This valve prevents the return of liquid through the silicone tube, in case of malfunction or sudden stop, allowing only one direction of flow within the conduction, interrupting what we call negative pressure, that is, the return of the fluid through the same inlet location. It is a small fitting that sits inline on your airline or any other aquarium tubing.

Read: How Long Should You Run An Air Pump And How Long Does It Last?

Air Stone: What Is It And Where To Place It In The Aquarium?

Generally, at the end of the air outlet hose, a porous stone is used which is called an air stone, also called an aquarium bubbler. There are porous stones of different sizes and types, some producing larger bubbles and others smaller.


There are some types that create a kind of ‘bubble curtain’. Thoroughly analyze the market models to have the best choice.

Also, you must note the amount and size of bubbles since a lot of movement in the water column can disturb some species of fish, mainly those that inhabit more still waters.

Now, regarding the placement of the air stone in an aquarium.

Where To Place An Air Stone In Aquarium?

Generally, an air stone is placed at the bottom of the fish tank, closer to the substrate. However, the air stone should not be buried into the substrate. If in your aquarium there are many places with low water movement, creating still water zones, you can place the air stone closer to those places.

Doing that will help in the circulation of the region, bringing more oxygen and moving possible debris that would be stuck there without being consumed by bacteria.

My Experience: I have three fish tanks in my home, and for two of them I have the air stone setup. I place the air stones in my tank in the bottom part of the tank touching the substrate but of course I don’t bury them 😀

Now you might be also wondering should I place the air stone closer to the corner of the tank or should I place at the central region? And the answer to that mainly depends on your personal preference.

The primary purpose of air stone is to create the bubbles inside the tank. These bubbles rise up and pop on the surface. The surface agitation happens and the gaseous exchange takes place which ultimately promotes the entrance of oxygen into the tank.

Whether you place the air stone in the corner part of tank or in the central part, as a rule of thumb, you shouldn’t worry much because more or less there output would be the same – to produce bubbles!

I personally place my air stones in the corner part of tank (in both of my fish tanks) and it works well since it works well with my fish tank setup.

I never noticed my fish gasping for air and coming to the surface with this setup. They do sometimes gasp but only when the air stone stops working but rest everything works well.

Times When Placing The Air Stone Near The Surface Makes More Sense:

#1. When Considering Breeding In The Tank

If you are considering breeding in the tank then, in such a case, it would be a good idea to place the air stone at the top part of the tank in such a way so that the fry don’t get hurt.

#2. To Reduce Air Pump Sound

Are you frustrated with your air pump’s continuous noise? Do you want some solution to this? Then one of the ways to solve this issue is to raise the air stone and place it near the surface of the tank water.

Remember water pressure increases with depth. So the more deeper in the fish tank you place your air stone, your attached air pump will have to work more and more against the increased pressure.

However, you can reduce the air pump noise by elevating the air stone and keeping it closer to the tank water surface. The principle behind this is simple, lesser the back pressure, lesser will be the vibration and hence the sound.

Personally speaking, I haven’t tried out this method yet. I actually use another tip of placing a soft material below the air pump to cushion the vibration.

And to be honest with you, in our home we are kind of habituated with air pump sound 😉 so our family members don’t bother much. But definitely, if reducing the air pump noise is your primary aim then you can try out that method of keeping the air stone closer to the surface.

How Do You Use An Air Pump In A Fish Tank?

It is very easy to proceed with the assembly of your equipment, once you have chosen the model of pump, hoses, and outlet to be used, just assemble them.

  • Connect the silicone pipe to the air outlet of the pump in question.
  • Cut the hoses to the required size and connect the valves of your choice, preferably, always use the check valve as a safety item and the air regulation valve, preferably leave them immersed.
  • Then connect the continuation of the hose and, at the end of this, the outlet, being the sponge filter or the porous stone or the chosen decoration, this last part must be immersed.

You can also watch this video from Fishaholic YouTube Channel on how to set up an air pump and air stone in an aquarium.

Final Thoughts

In short, the air pump “pushes” atmospheric air into the water column inside the aquarium. Thus, injecting air into the system, breaking the surface tension, and also helping and maintaining circulation, which prevents it from creating dead zones (zones without oxygen) inside the tank, help in the oxygenation of water and gas exchange on the surface.

And regarding the placement, it is best to place the air pump near the top of the aquarium water level.

So I hope now your all doubts related to the aquarium air pump are cleared. Please share this article if you found it helpful. And if interested, you can visit my YouTube Channel eFishkeeping.

Read Next:

That’s it! Thanks, enjoy fishkeeping 🙂


Wikipedia – Air Stone

Aquarium Coop – Aquarium Air Pump – Aquarium Air Stones

Tropical Fish Care Guides – Fish Tank Air Pump

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