What Are Aquarium Air Stones? (And Should You Use Them)

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An air stone is something that diffuses air that is being pumped into your aquarium through an air pump. They are small and often blue or black in color and come in all shapes and sizes. And for such a little piece of equipment, there sure is a lot of misleading information on them floating around.

So if you’re serious about understanding what these devices are and why they are the one piece of equipment that should be in every tank, even if you just have a planted tank, then read on as I will be revealing some seriously important facts and killing a few fishy myths about air stones.

Key Takeaways

  • Air ‘stones’ are made from many materials other than stone
  • Air stones work through agitation, not diffusion
  • Air stones are necessary for all aquariums, even those without fish.

Introduction – What Are Aquarium Air Stones?

First off, an air stone, also known as a bubbler, is not always made from stone. In fact, more and more they are no longer being made of natural objects like silica, porous stones or lime wood, but rather glass, ceramics and even plastics are all being used to make these ‘stones’.

Secondly, although these stones do contribute to incorporating O2 into the water of your aquarium, this is not the result of the bubbles diffusing their oxygen into the water. At least not to the degree that everyone keeps saying it is.

Thirdly, air stones aren’t just there so your fish can breathe. Even planted tanks with no aquatic life other than the plants can still greatly benefit from having an air stone.

These cheap little devices do a lot! And they should be in every tank.

In fact, have you ever seen some breeding tanks, or even those tanks at a fish restaurant? They are usually completely bare of anything other than one thing, yup, an air stone. Just something to take note of.

Why Are They Important?

In order to really understand what an air stone is and why it’s imperative to include one in your tank, we’re going to briefly need to understand a little science.

Obviously for any tank to maintain aquatic life there needs to be some oxygen in the water.

Depending on a number of factors including how many fish you’re keeping, plant life and the consistency and size of water changes all play a role in the amount of O2 that is either absorbed or expelled into the water.

But another part of having fish and even plants is the CO2 they themselves expel. Plants can do a lot to absorb CO2 in a fish tank, but at night, they are releasing CO2 as well as your fish. So excess carbon dioxide needs to be taken out while the oxygen needs to be put in.

In order to do this we need to create an environment that includes optimal gas exchange.

And optimal exchange occurs due to agitation of the water’s surface, not because air bubbles are diffusing dissolved oxygen into the water from your air stone.

Both O2 and CO2 levels need to be optimized according to your tank requirements. And aquarium air stones are the very best and most cost effective way of doing this.

Why Are They So Effective?

In a recent scientific study, scientists concluded that water (such as in the ocean for this study) that is agitated from below the water’s surface creates a more efficient effect on absorbed oxygen levels. Or adding dissolved oxygen and expelling carbon dioxide from a body of water.

‘Breaking of the water surface from below has considerably more effect in increasing the exchange of oxygen…’ Although they did not understand exactly why this is the case, it definitely demonstrates why an air stone would be so effective.

This study also backs up an avid fish keeper’s theory in his video where he uses an oxygen meter to take readings from a bunch of different fish tanks all using different methods of aeration and surface agitation.

Although not as ‘scientific’ as the other study, he also came to the same conclusion that tanks with an air stone always had considerably more oxygen in their water than any other aeration method tried, by far.

So while your aquarium fish tank may benefit a tiny bit as the air bubbles rise diffusing into your water as they float to the top of your tank, it’s the action of the fine bubbles reaching the surface and causing disruption to the surface that is actually doing the work to produce more oxygen.

The bubbles bursting at the top of your tank speeds up the gas exchange allowing excess CO2 to escape while also absorbing oxygen. So the more bubbles and fizz happening, the better your fish tank will be oxygenated.

What Are Some Other Benefits?

Aquarium air stones aren’t just for increasing oxygen levels in your home aquarium. There are actually many benefits of having an air stone in your aquarium fish tank.

Often times there are places in a fish tank that you just can’t get to in order to clean. These sorts of spots collect debris and fish and plant matter that breaks down and releases CO2 and other harmful gases into the tank.

Aquarium air stones work to improve water circulation that keeps oxygenated water flowing throughout the entire water column, including any dead spots which is important for maintaining a healthy environment, especially in large aquariums.

The steady stream of tiny bubbles rushing up in your aquarium also looks nice and can be soothing to listen to. I always enjoyed the noise of my air stone at night and found it very relaxing, almost like waves on the ocean.

And I’ve even had fish that seemed to enjoy swimming in and out of the bubbles, almost like they were playing. Good exercise for them too if your fish are a bit fat!

How to Use Them?

Buying, installing and using an aquarium air stone is one of the easiest things you can do as an aquarist. And the most beneficial too!

When you get your new air stone, you’ll also need to grab an air pump to push air to your stone. Both the aquarium air stone and air pump can be found at any fish store and are only a few dollars. If you have the funds get one with a control valve so you can adjust the amount of air pressure.

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For smaller aquariums, just get a cheap all in one set up that will work properly until you get more serious about the hobby. Just be sure the noise level isn’t too bad as some pumps can be really loud.

You’ll also need some tubing to connect the stone to the air pump. They’re usually clear plastic and again, they’re super cheap. The length depends on where you’ll place your air stones in the fish tank. There are a lot of options that are 25 feet of hose plus all types of connectors.

As far as what stone is the best or what material to buy, again, go with an inexpensive option in the beginning. Most air stones last up to 5 years plus and can be cleaned easily enough if they get clogged.

For the price, there really isn’t a ‘best’ material although I’d stay away from anything plastic and stick to natural materials like ceramic, glass or silica air stones.

How to Clean Them?

Although air stones are quite cheap and most aquarists just toss them in the garbage and buy new ones, they can be easily cleaned if they start clogging up or just get really dirty with algae.

One of the easiest ways to clean an old air stone is to soak it in hydrogen peroxide overnight. In the morning rinse it off in fresh water for five minutes then let it completely air dry. Once dry, it’s clean enough to go back into your aquarium.

If you have hard water, soaking your air stone in a solution of equal parts vinegar and water overnight will help remove all the calcium buildup. The next day rinse it off well, then let it soak in freshwater for an hour before returning it to your tank.

Airstones or Sponge Filters?

Although these two may seem similar and both work with air pumps, they are still very different. An aquarium air stone only diffuses the air being pumped through it while a sponge filter uses the air pump to filter out debris and breed beneficial bacteria.

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Sponge filters usually produce large bubbles rather than the tiny bubbles an aquarium air stone creates which isn’t as beneficial for water movement as a stone is.

So which is better or more important? That totally depends on if you have some sort of biological filtration already. If not, then both are equally important and both should be used.

In fact, one way to get the best of both worlds is to use the air stone inside the filter connected to an air pump. That way you’re still getting the water circulation effect while filtering your water at the same time.


Are air stones good for aquariums?

Yes, air stones are very good for aquariums. They provide the necessary aeration needed for fish to breath in closed aquarium environments.

Where should the air stone be in a fish tank?

The air stone should be placed in a corner or out of the way of focal points within your aquarium.

How long do aquarium air stones last?

Provided you purchased a quality air stone, they can last from a year to five or more years with proper cleaning and care.

Can fish live without air stones?

Fish can live without an air stone if you have adequate aeration through some other means like live aquatic plants or moving water.

Are air stones good for fish tanks?

Yes, air stones are great for fish tanks. They help with water oxygenation and help move around nutrients and waste products in your tank water so they can be sucked up by your filter.

Wrapping Up…

After reading all of this it should be pretty obvious that the easiest thing you can do to improve the water quality of any fish tank is to simply use an air stone connected to an aquarium pump in your tank.

This little inexpensive piece of equipment can do more to oxygenate your tank’s water and increase circulation than most other things combined.

With their low cost, ease of maintenance and many benefits, why wouldn’t an aquarium air stone be your very first investment!

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