Best Air Stone for Hydroponics in 2023
Guide to the 7 Best Air Stones for Hydroponics in 2023
An air stone is essential for successful hydroponic growing because it is responsible for delivering usable oxygen to your plants’ roots. Air stones come in a variety of shapes and air flow capacities, so selecting the right one for your system is critical.
This article will go over 7 of the best air stones for hydroponics, with options for small and large home setups.
You’ll also learn about the science behind them, the best size for your needs, and general usage and maintenance guidelines.
So let us get into the specifics of hydroponics air stones!
- Medium Hydrofarm Active Aqua ASCM Air Stone Cylinder
- Green/Blue CNZ® Fish Tank Air Bubble 2-Piece Air Stone Bars (8-inch)
- VIVOSUN 5 x 5 Inch Air Stone Disc with Shell and Sucker for Aquarium, Fish…
- AQUANEAT Air Stone 2 Pack, Large Air Stone Cylinder, Aerator Bubble…
- Air Stone Diffuser Release Tool for Pawfly Aquarium 4 Inch Air Stone Disc…
- Wenshall 1.6 inch Air Stone, Aquarium, Fish Tank, and…
- Active Aqua ASCM Air Stone Cylinder from Hydrofarm
This air stone is available from Hydrofarm in three sizes:
- 1.4 x 1.7 in.
two by two inches (featured here)
two by four inches
The medium size is highlighted here because it is versatile enough to be used in everything from a 5-gallon bucket to a 20-gallon drum.
This stone has the advantage of sinking to the bottom of your container and remaining there. This saves you time reaching into the tank to repair your air stone while also ensuring maximum water circulation and oxygenation.
Furthermore, the stone’s micropores produce a large number of small, easily absorbable bubbles. This is a workhorse that does not disappoint!
NOTE: To produce the correct volume of bubbles, this stone requires a fairly powerful pump. A pump with at least 240 gallons per hour output, such as this 6-watt model from Hydrofarm, should suffice.
Excellent for a wide range of reservoir sizes and shapes.
Excellent, consistent bubble production
Stays at the tank’s bottom.
There are three size options.
A powerful pump is required.
- CNZ Air Bubble 2-Piece Air Stone Bars for Fish Tanks
2-Piece CNZ Fish Tank Air Bubble Air Stone Bars
The bar is a “classic” shape for air stones that works well in Deep Water Culture. Their elongated shape provides excellent bubble coverage and aeration, particularly in larger rectangular reservoirs.
These bar air stones come in a two-pack and are available in five different lengths:
- 4-inch, 6-inch, and 8-inch (featured here)
You can separate them into different containers, or you can put both air stones in one reservoir for maximum bubbles.
So, no matter what the dimensions of your reservoir are, you should be able to find a size that fits perfectly.
One disadvantage is that the long, thin shape has a tendency to float, and these are already quite light. Suction cups on the airline tubing may be required to keep your air stone in place.
Ideal for rectangular tanks
Size options are limited.
It generates a long stream of fine bubbles.
It floats easily.
- Air Stone Bubble Pawfly 4-Inch
4-Inch Pawfly Air Stone Bubble
At 20 litres per minute, this half-dome shaped air stone produces a large volume of small, consistent bubbles, making it one of the more powerful air stones on this list.
Its hemispherical shape has no edges or corners to obstruct the flow of fine, uniformly-sized bubbles. This is ideal because small bubbles allow your plants’ roots to absorb oxygen more easily.
The connection for the tubing to the air pump on these bubble-shaped air stones is directly on top, rather than on the side, as it is on disk-shaped air stones. This eliminates the possibility of a kinked line impeding airflow.
It also simplifies setup and maintenance, especially if used in a narrow five-gallon bucket DWC.
If you prefer, Pawfly sells this stone in a two-pack.
One thing to keep in mind: this stone requires a lengthy pre-soaking period. Pawfly recommends soaking for 3 hours, but users report much better results after soaking for at least 6-12 hours.
A large surface area produces exceptional bubbles.
Simple tubing connection
Tubing kinks are less likely.
Pre-soaking time is required.
- VIVOSUN 5″ Air Stone Disc with Shell
5 Inch Air Stone Disc with Shell by VIVOSUN
Vivosun’s disc-shaped air stone is another excellent choice for shallow reservoirs. There are three sizes to choose from:
5-inch (featured here)
Because of its low profile and three sizes, this is one of the best air stones for DWC because it can fit almost any setup.
It produces a steady flow of small, fine bubbles at 14 litres per minute, which is ideal for optimally oxygenating water.
Both the 4-inch and 5-inch options are 0.8 inch tall and are suitable for reservoirs holding 5 to 15 gallons.
Just keep in mind that the 8-inch size option is a beast. It stands 1.5 inches tall and requires an air pump with a minimum output of 16 watts and larger 8 mm air line tubing.
It’s probably more power than you need, unless you’re working with a large-scale reservoir.
Size options for any tank configuration
Outstanding bubble production
Airflow is excellent.
For many home hydroponic tanks, the 8-inch option may be too large.
AQUANEAT 2 PACK AIR STONE
2 Pack AQUANEAT Air Stone
With two stones in a pack and three sizes to choose from, these Aquaneat air stones are a great buy.
With two stones, you can create two separate DWC reservoirs. Furthermore, three size options allow you to customise based on the volume of your reservoir.
You have the following size options:
two by two inches
2 x 4 inch (featured here)
6 inches by 2 inches
The smallest size (2 x 2 inches) is suitable for 5-gallon buckets to 10-gallon containers. The medium-sized (4 x 2) air stone is ideal for 20-gallon or larger containers.
The small and medium sizes are ideal for home hydro systems. However, the largest size (6 x 2) is ideal for large-scale setups or commercial growing.
These air stones produce a large amount of bubbles, and the top-end hose attachment prevents your tubing from becoming kinked against the side of your reservoir.
Reviews also mention that these are heavy and sturdy, so they’ll stay firmly anchored at the bottom of your DWC.
One thing to keep in mind: Don’t shorten the pre-soaking time. Some users have reported that if the stones aren’t soaked long enough, they won’t work properly, so allow for some extra set-up time.
Heavy structures will not float.
Outstanding power and bubble production
Pre-soaking time is required.
6-inch Pawfly Air Stone Disk
4-Inch Pawfly Air Stone Disk
Pawfly’s 4-inch air stone is a flat round disc that sits on the reservoir’s bottom and emits a steady stream of small-diameter bubbles.
Because disk-shaped air stones have a flat, wide design, they may try to float away if there isn’t enough weight to keep them in place. One nice touch is the presence of three small suction cups on the stone’s outer rim.
This makes it simple to secure your air stone to the bottom of your hydroponic tank.
With a pumping rate of 12 litres per minute, this air stone is ideal for small-to-medium-sized DWC reservoirs of 10 gallons or less.
Ideal for a 5-gallon bucket
Suction cups are included.
There is plenty of airflow.
Not powerful enough for larger setups.
- Small Round Wenshall Air Stones
Small Round Wenshall Air Stones
Finally, Wenshall’s four-pack of air stones is small but powerful.
Each stone produces 2 litres of air per minute. They produce a large number of bubbles for their size while remaining heavy enough to sink to the bottom and remain there. Not bad for such a small piece!
If you’re just getting started with air stone hydroponics, typically DWC, these can be an excellent choice. They fit easily inside smaller reservoirs and are inexpensive.
You can also combine two for increased aeration or larger reservoirs.
However, keep in mind that the minimum airflow for each gallon of water should be about 1 LPM. Even if you use all four stones together, these stones aren’t ideal for setups larger than 8 gallons in volume.
Ideal for small-scale installations.
Price point that is reasonable
Larger hydroponic tanks are not recommended.
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What Is the Purpose of an Air Stone?
To put it simply, an air stone adds oxygen to water.
At the bottom of your reservoir, air stones emit a steady stream of fine bubbles. As the bubbles rise to the water’s surface, they pass through the plant’s root web, where oxygen is absorbed and cellular respiration begins.
This dissolved oxygen also improves nutrient uptake by the roots from the hydroponic solution. In fact, even if you create the most nutrient-rich water possible, a lack of oxygen actively prevents your plant from absorbing the nutrients it requires!
Because adequate oxygenation is critical, many hydroponic growers supplement their systems with hydrogen peroxide (H202). H202 releases oxygen as it degrades (along with many other wonderful things!)
Bonus: If you’re interested in learning more, check out our post on H202 for hydroponics.
However, air stones cannot oxygenate your hydroponic tank on their own. An air pump is also required to generate the airflow that passes through the air stone.
The two pieces working together produce the oxygenation that allows hydroponic growing to produce such high yields. When the roots receive enough oxygen, the plant grows faster and processes nutrients more efficiently.
Air Stone Varieties
Air stones come in a variety of shapes and sizes, with some being better suited to hydroponics than others.
The following are the best air stones for hydroponics:
Cylinder Bar Disk Bubble (or Hemisphere)
The size and shape of your air stone should be determined by the size and shape of your reservoir.
A bar-shaped air stone, for example, would be ideal in a large rectangular reservoir but would be ineffective in a round five-gallon bucket.
A disc would generate enough bubbles for a bucket but not enough coverage for a larger reservoir.
Some cylinder stones, unless pre-weighted, tend to topple over and roll around more easily than other shapes. The ones we’ve discussed here are already heavy, so they should stay put.
However, if you prefer a different brand that begins to float or move, you can secure it with a suction cup on the airline tubing. This Pawfly suction cup multi-pack is inexpensive and will last a long time.
Is it necessary to use airstones in hydroponics?
Airstones are an essential component of a hydroponic system because without mechanical aeration, the plants in the hydroponic water reservoir will not be able to “breathe.” Plants absorb oxygen not only through their leaves, but also through their root system.
Plants may not appear to be able to take in oxygen through the ground, but in soil loose enough to support plant life, there is enough oxygen in the topsoil to sustain the plant. Because there is no soil, the hydroponic gardener must provide this oxygenation.
Airstones are useful for more than just oxygen dispersal in hydroponic reservoirs. They can also be used to reduce the amount of time required to dechlorinate water. Tap water is unsuitable for hydroponics because it is too alkaline and contains chemical contaminants such as chlorine. To be useful in a hydroponic setup, the reservoir water must be dechlorinated and pH stable.
Oxygen Dissolved in Hydroponics
Plants consume carbon dioxide and emit oxygen as a byproduct of photosynthesis, but many gardeners are unaware that plants require oxygen exposure to both their leaves and root systems. The plant’s root system will fester and die if it does not have access to oxygen at the root level.
One of the reasons plants die when overwatered in a soil-based gardening system is that the soil becomes too saturated to hold dissolved oxygen, strangling and killing the plant. A hydroponic aeration system simulates the air present in the soil in hydroponics.
By agitating the water, these systems introduce dissolved oxygen into the hydroponic reservoir. This is typically accomplished by pushing air through a piece of pumice, resulting in a curtain of small bubbles that efficiently dissolve oxygen into the water.
Temperature is one environmental factor that influences oxygen saturation in a hydroponic reservoir. The more warm your hydroponic system is, the more aeration is required to ensure that your plants get enough oxygen.
How Much Does Aerating a Hydroponic System Cost?
In general, aerating a hydroponic system does not require much electricity, but how much it costs to aerate depends on the size of your hydroponic operation. A hydroponic farm will obviously use a lot more electricity for aeration than a small backyard hydroponic system.
To adequately aerate a deep water culture, a good rule of thumb is to pump one litre per minute of air into a hydroponic reservoir. This means that if you’re using a 100-gallon reservoir, you’ll need an air pump capable of producing 100 litres of air per minute.
Other than the airstones, some of the costs associated with a hydroponic aeration system are as follows:
The device that pumps air through the airstones and into the hydroponic reservoir is known as an air pump. The larger your hydroponic system, the more powerful the air pump.
Plastic aquarium tubing connects the airstone to the pump and shunts air from the pump through the stone to create bubbles.
If you use a bubble bucket hydroponic system, you’ll need an airstone and tubing for each bucket, as well as check valves to ensure that air only flows in one direction (towards the airstone) and that water doesn’t drain back out of the tank and through the aquarium tubing if the pressure changes or the air pump fails.
Because hydroponic aeration supplies are inexpensive, it’s a good idea to always have some on hand in case of a pump failure or other similar issue. While aeration systems are typically run throughout the day, they can be programmed to shut down at the end of the day with the exception of intermittent 15-30 minute intervals to maintain oxygenation levels.
What Materials Are Used to Make Airstones?
Airstones can be made from a variety of materials, including:
- Stone made of ceramic (pumice)
Glass and wood (limewood)
Each of these types of materials has advantages and disadvantages. Wood-based airstones produce a finer curtain of bubbles (and thus more dissolved oxygen into the water), but they are prone to clogging and may not be as powerful as a pumice or ceramic airstone.
When selecting an airstone, keep the price in mind because, regardless of the type, they will need to be replaced within a couple of months to maintain their effectiveness. You won’t realise you’re losing oxygenation levels in your reservoir until you notice signs of oxygen deprivation in the plants themselves if you don’t replace your airstones on a regular basis. Usually, the damage has already been done at that point.
Is an Air Diffuser the same as an Air Stone?
Air stones and air diffusers serve the same purpose in a hydroponic system: to oxygenate the water. They are, however, distinct tools.
An air stone is essentially a very porous rock that the air pump forces oxygen through.
They’re cheap and efficient for aquariums and smaller setups. However, the more you try to scale them up, the less powerful and consistent they become.
Air diffusers are made of flexible tubing that can be shaped to fit the reservoir to which they are intended.
They evenly distribute bubbles throughout the reservoir and are less prone to clogging or breaking than air stones. They are prefered by advanced hydroponic gardeners as well as commercial hydroponics growers.
What Size Air Stone Do You Require?
In general, the more bubbles, the better.
While there can never be too much oxygen in the water, there can be an overpowering bubble stream. You want to aerate the roots rather than stress them by exposing them to a strong current.
In hydroponics, the bare minimum for an air stone is 1 litre per minute of airflow for each gallon of water in your system.
So, for a 5-gallon bucket, you’ll need at least 5 LPM of airflow, a 15-gallon reservoir, 15 LPM, and so on.
This is when purchasing a set of multiple air stones can be extremely beneficial. If one isn’t enough, you can easily add one or more to your reservoir without having to select and buy a larger stone.
Air valves, such as these small plastic ones, can also be used. You can easily control and adjust the bubble rate of your air stone using a valve.
Should You Soak an Air Stone Before Using It?
Yes, all air stones must be soaked before use.
While some manufacturers claim that their stones can be soaked in as little as one hour, users appear to get better results after soaking them for at least six hours and up to a day.
If you clean your air stones every time you clean your hydroponic tank, you’ll get the best airflow from them. A weekly or biweekly cleaning schedule is usually recommended.Best Air Stone for Hydroponics in 2023
Scrub the outside of the air stone thoroughly with a bristle brush or an old toothbrush, then rinse it several times in clean water. Avoid using soap because it can be difficult to remove completely.
You can also do this whenever you notice that the volume of bubbles released by your air stone has decreased, as clogging is frequently the cause of this.Best Air Stone for Hydroponics in 2023
Is an Air Stone Required in All Hydroponic Systems?
Deep Water Culture (DWC) is the only hydroponic system that requires an air stone and pump. Other systems, such as Ebb and Flow, Nutrient Film Technique, and drip systems, use different methods to deliver adequate oxygen to your plants’ roots.Best Air Stone for Hydroponics in 2023
All of these methods of growing are known as active systems, and they all rely on electricity to circulate water and expose plants to oxygen.
However, there are passive hydroponic growing methods that do not require electricity or airflow (and thus, no air stone).
All passive hydroponic systems are variations on the Kratky method. They entail suspending the plant roots over a nutrient-rich water solution and simply letting the plant absorb the water as it grows.Best Air Stone for Hydroponics in 2023
These systems are suitable for plants with rapid growth patterns and little or no fruit production. But that doesn’t mean you don’t have a wide range of plants to choose from! We compiled a list of Kratky-friendly plants, so check it out for some inspiration!
Also, our post on Mason jar hydroponics is a great example of passive hydroponics on a small scale.Best Air Stone for Hydroponics in 2023
Frequently Asked Questions on Air Stones for Hydroponics
In hydroponics, how long do air stones last?
Should I keep my air stone turned on all the time?
Yes! Plant roots require oxygen to function properly, so they don’t require a break from the bubbles.
How big of an air stone do I need for hydroponics?
In hydroponics, the bare minimum for an air stone is 1 litre per minute of airflow for each gallon of water in your system. So, for a 5-gallon bucket, you’ll need at least 5 LPM of airflow, a 15-gallon reservoir, 15 LPM, and so on.Best Air Stone for Hydroponics in 2023
What is the function of air stone in hydroponics?
Air stones are a great tool for adding oxygen and circulating nutrition to your hydroponic growing system because oxygen is very important for hydroponic growing systems. They can generate fine bubbles to replace oxygen, extend the life of your nutrient solution, and keep roots healthy.Best Air Stone for Hydroponics in 2023
How big of an air stone do I need?
The air stone’s shape is also a source of concern. Most filters and ‘action ornaments’ that can accept an air stone will work best with 1″ (2.5cm) long, 1/2″ (1.25cm) diameter air stones.
Air stones are a useful and simple addition to home hydroponic systems that can elevate your setup to the next level.Best Air Stone for Hydroponics in 2023
Although there are many hydroponics air stones to choose from, it’s difficult to go wrong. Even a small amount of oxygen added to a hydroponics system will result in large harvests.
Choose the best shape and size for your reservoir, and you’ll reap the benefits during your next harvest!Best Air Stone for Hydroponics in 2023