Hydroponic air stones are the backbone of any deep water culture system. Without air stones, your root zone would not get enough oxygen and your plants would drown! Air stones are porous and diffuse oxygen from the air pump into gentle bubbles that work themselves through the roots of your plants in order to provide the oxygen levels they need.

Read on to learn how to pick out the right air stone!

How Do Air Stones Work?

Air stones work alongside air pumps to create oxygenated bubbles in your hydroponic system. The air pump pumps air into a hose that connects to your airstone, which then diffuses the supply of oxygen into bubbles.

Why Do Plant Roots Need Oxygen?

There are many reasons that plant roots need oxygen.

One reason is to avoid root slime. Root slime limits nutrient and oxygen absorption by covering the roots. Lack of water movement and lack of oxygen can both lead to root slime. Thankfully, airstones provide both!

Oxygen also helps to prevent waterborne diseases. Fungi and bacteria love to develop on roots that are low on oxygen.

Lastly, and perhaps most importantly, roots need to be able to breathe. Plants are living beings, and just like all living beings, they don’t like being suffocated!

What Hydroponic Systems Use Airstones?

Deep water culture (DWC) is the only hydroponic system that utilizes airstones.

In DWC, the roots stay submerged in the water reservoir their entire lives. Plants are suspended above the reservoir in a tray, and the roots dangle below into the nutrient-rich solution.

This is all fine and dandy, except for the fact that the plants will drown without oxygen! That’s where airstones come to the rescue.

How to Choose The Best Airstone

When you’re choosing an airstone, you need to think about four things:

  • Jetting volume
  • Dimensions
  • Pump wattage
  • Reservoir size

How Much Air Do I Need In My DWC?

In DWC hydroponic systems you need 1 liter of air/minute per 4 liters of nutrient solution.

Airstone Materials

Two main two materials used to make airstones include aluminum oxide and silica.

Aluminum Oxide

Most airstones are made out of aluminum oxide. This is a strong, long-lasting material that will make it up to five years if you take care of it.

The bubbles created by aluminum oxide airstones tend to be around 3 millimeters in diameter.


Silica airstones are cheaper than aluminum oxide airstones but aren’t as durable. They can also affect the pH of your water reservoir because silica is alkaline.

Airstone Shapes

Airstone shapes include cylinder, bar, disc, ball, and cuboid.


The majority of airstones are cylindrical. They work well with nearly any reservoir.

Cylinder airstones range from half an inch to two inches in diameter and provide anywhere from one to five liters of air each minute.

Cylinder airstones do best with air pumps that have between two and eight watts depending on what size they are.

Bigger airstones need a higher wattage.


Bar airstones are designed for rectangular reservoirs. Since they’re lengthy, they’re able to distribute the bubbles all throughout the reservoir.

Bar airstones range from about five inches to a foot long! They use air pumps anywhere from two to 10 watts. Air flow ranges from about one to 15 liters of air each minute.


Disc airstones are small but mighty! They reach up to four inches in diameter and are great for deep reservoirs.

Disc airstones only need 2-4 watts of power and deliver and airflow of 2-12 liters/minute.


Ball airstones are also good for deep reservoirs. They tend to be bigger than cylinder and cuboid airstones.

A 2 inch ball will give an airflow around 2 liters of air per minute if used with a 4-8 watt air pump.


Cuboid airstones are perhaps the least popular, although worth mentioning regardless. They’re best used in small systems.


Do You Need An Air Stone In A Hydroponic System?

You absolutely need an air stone in a hydroponic system. Without the supplementation of oxygen, your root system can down. Oxygen is vital to the root system so it can breathe and uptake nutrients. In addition, oxygen and water movement ward off fungi and diseases.

Can You Have Too Much Air In Hydroponics?

You can have too much air in hydroponics. If your airstone is working too well and providing too much oxygen, spread out perfectly- then your plant roots won’t have as much of an incentive to grow deeper. Shallower roots will result in less plant growth.

What’s The Difference Between An Air Stone And A Bubbler?

The difference between an air stone and a bubbler is that an air stone is a porous object that diffuses oxygen to create bubbles. Meanwhile, bubblers have holes drilled into them to make the bubbles.

Do Airstones Make A Difference?

Airstones make a huge difference. In fact, they can be the difference between life and death! If you don’t provide oxygen to your plant roots, they can quickly drown. 

Will Air Stones Raise pH?

Silica air stones can affect the pH of your water.

How Do You Stop Airstones From Floating?

You can stop airstones from floating by using small suction cups. Attach the cup(s) to the bottom of your airstone, and then press it onto the bottom of your reservoir. Make sure your hands are completely clean, or even better, do this when you’re changing the water so as not to introduce any potential bacteria or diseases to your reservoir and plants.

How Do You Oxygenate Hydroponic Water?

You oxygenate hydroponic water with an air pump and an airstone. The air pump connects to a tube, which connects to the airstone. The airstone then uses its pores to create tiny bubbles to oxygenate your water. You will need to choose your airstone based on a few factors, including how big your reservoir is and how many watts your air pump uses.


To be blunt, your plants would die without proper oxygenation! Airstones play a vital role in DWC hydroponic systems. Since the roots are suspended indefinitely, they have no way to breathe. Airstones diffuse oxygen into bubbles so that your plant roots can breathe and uptake nutrients and air.

Check out the rest of our blog for more beginner tips!