Active hydroponic systems use air pumps to increase oxygen concentration in the form of bubbles. Like you, I also once wondered: How many bubbles is too much in a deep water culture (DWC) hydroponic system?
Generally, providing too many bubbles in hydroponics is a concern since it can increase water temperature, dissolve hydroponic nutrients, and make the solution more acidic. This could be a result of using air pumps that are too strong or using too many air stones.
You might be asking right now: How should I choose an air pump for deep water culture (DWC) hydroponics? Are there factors to consider? These questions will be answered at the end of this article.
It is possible that gardeners provide too many air bubbles in their deep water culture (DWC) hydroponic systems. This could be through using too many air stones or using air pumps that are too strong.
Too many air bubbles are produced in a hydroponic system when a gardener puts so many air stones in a single deep water culture (DWC) bucket.
Another possible instance is using an air pump that releases air pressure that is too strong for the system like a small hydroponic set-up. The compatibility of air pumps with the hydroponic system is also a huge factor to consider. Today, you are lucky because I will share a secret about this later in the article!
Before we dive into that, let us first review the purpose of bubbles in deep water culture (DWC) hydroponics.
Bubbles are necessary for deep water culture (DWC) hydroponics because they 1) elevate dissolved oxygen, 2) prevent algae reproduction, 3) regulate water temperature, and 4) displace hydroponic nutrients.
Air pumps create bubbles that promote gas exchange in hydroponics. These bubbles let oxygen in and carbon dioxide out of the water’s surface. With higher dissolved oxygen levels, the roots can support their function to deliver nutrients and water to the plant.
Dissolved oxygen is just the amount of oxygen present in water. It may sound too technical, but I assure you, it is not some kind of oxygen with a superpower! So if we compare this with aquatic systems, dissolved oxygen is what enables fishes to breathe!
The same thing goes with the relationship between dissolved oxygen and your plant roots. Plant roots also breathe! They do it in a process called cellular respiration. So imagine if your plants only sit in stagnant water. Like us, they might also drown!
This is the major reason why air pumps are advised for hydroponic systems, specifically for deep water culture. Adding an air pump to your DWC system also adds access to oxygen for your plant’s roots.
When oxygen is added, the roots are capable of delivering the water and nutrients supplied to every part of your plant. This process further promotes and fuels the growth of leaves, flowers, and, more importantly, the fruits!
Air pumps cause water movement in the hydroponic solution which is essential in preventing algal blooms.
Hydroponic systems are enriched with nutrients. This is a well-known fact. However, algae thrive in stagnant water with rich amounts of nutrients, light access, and warm temperature.
So imagine pairing your nutrient-enriched water with stagnancy. You have to expect algae growth after just a few days!
To support this further, algae reproduction commonly happens in water drums, ponds, and other stagnant bodies of water.
Since air pumps generate water movement, bubbles produced increased water temperature in hydroponic systems. This is beneficial for those who live in cold places, as it balances the surrounding temperature around the hydroponic nutrient water.
Providing your system with bubbles can also increase the temperature of your hydroponic solution. This is one of the reasons why too many bubbles could be disadvantageous for your hydroponic plants. More of this will be discussed later.
Learn more about this in our article on the best temperature for deep water culture hydroponics.
The water movement caused by bubbles moves the hydroponic nutrients all throughout the water reservoir. This results in the optimum usage of all the dissolved nutrients.
Have you ever made juice from a powdered mix? If yes, I think you can relate to this.
After stirring the powdered juice, there are times when not all of the powder is dissolved. Some of it remains at the bottom of the pitcher. The same thing might happen in hydroponic systems.
When you are using dry nutrients, there is the additional task of dissolving it. If you are good at stirring it before using it as a hydroponic nutrient, I think you are good for now. But, solidification might still happen due to other environmental factors such as temperature and pH levels.
Considering this, the bubbles from the air pump—together with the motion it induces to the nutrient water—serve as a continuous stirrer for a hydroponic system. This ensures that no nutrient is left at the bottom of the reservoir and that all of the nutrients are used efficiently.
Learn more about this in our article on hydroponic nutrients.
More bubbles can be achieved in hydroponics by 1) using more air pumps, 2) shifting to stronger air pumps, and 3) using unclogged air stones.
Adding more air pumps generates more bubbles, thus more oxygen for the hydroponic plants.
Let us assume you have a 20-gallon hydroponic reservoir. Do you think a small air pump could handle that big amount of water?
Absolutely not! This is the reason why you should always account for the compatibility of your hydroponic reservoir with your air pumps.
Thus, you should check the capacity of the air pumps you purchase. If it cannot handle your hydroponic reservoir, you may opt to buy more air pumps.
Choosing air pumps that have bigger wattage and can support more water volume is a way to produce more bubbles.
In relation to the situation above, if you want to save money, choose stronger pumps.
An example of this is HITOP, which is available on Amazon. This one is good to use in bigger hydroponic systems as it can support 20-100 gallons of water. It also has 2 hose outlets that you can use separately.
To ensure the release of more bubbles in an air stone, one should make sure that it is free from any clogs such as dirt, plant debris, or growing mediums.
When an air stone is clogged, it might not supply the expected amount of oxygen your hydroponic water needs.
Thus, it is advised to always check if there is any blockage in air stones. Possible agents that can block your air stones include plant debris, growing mediums, and even dirt.
To clean your air stones, you could soak them in diluted bleach for 24 hours. You can extend this duration if they are really clogged badly! The ratio for bleach must be 1 part bleach to 3 parts water.
If you are using food-grade hydrogen peroxide, dissolve 2-3 teaspoons per gallon and soak your air stones overnight. After such time, rinse them well with clean water and put them back in your system.
Too many bubbles are not recommended for hydroponic systems. Excessive bubbles can raise the temperature of the nutrient water, concentrate nutrients, and change the pH of the hydroponic solution.
As the water temperature increases, evaporation may occur. When this happens, your nutrient solution will be more concentrated. This means the dissolved nutrients in your solution will now be greater in their amounts because water is transforming to its gas form.
Another thing that could happen after these series of reactions is the swaying of pH. When nutrients become concentrated in your hydroponic solution, it could be more acidic because most of the nutrients for plants are acidic in nature.
Choose an air pump with wattage equal to the gallon capacity of the hydroponic reservoir. Also, an air pump should deliver 500 to 600 cubic centimeters of air into the nutrient water per minute.
So for example, if you have a 5-gallon hydroponic reservoir, you will need a 5 watts air pump for that.
Do not worry about how to find this information! Most market-available air pumps usually indicate their capacity in gallons. To help you decide, here are some available air pumps on Amazon along with their capacities.
Aquaneat can support 10 gallons of water.
Hygger can handle 1-15 gallons of hydroponic water.
Are air pumps needed in hydroponics?
Air pumps are necessary for deep water culture hydroponics. This is because the plants in this system are submerged in water for a long period of time. Thus, they need an additional source of oxygen to carry out their biological processes and survive.
How long should air pumps run in hydroponics?
Air pumps should run on and off in thirty-minute intervals for hydroponic systems such as nutrient film technique (NFT) and ebb and flow systems. On the other hand, deep water culture (DWC) needs aeration 24/7.
Is it possible to overwater deep water culture (DWC) hydroponics?
Yes, plants in deep water culture hydroponics could be overwatered. This might happen when you submerged your plant’s roots in water for a long period. When this happens, the roots may drown and may not function properly in distributing nutrients and water to the other plant parts.
More and/or stronger air pumps and several air stones in hydroponic systems could produce too many bubbles, which is not optimum for a hydroponic system.
On average, bubbles elevate water oxygen levels, prevent algae blooms, regulate water temperature, and displace hydroponic nutrients. However, too many bubbles could also increase nutrient water temperature that may lead to dissolving nutrients, and further, make the water more acidic.
The best air pump for a hydroponic system has a wattage equal to the reservoir’s capacity in gallons. Furthermore, an airflow of 500 to 600 cubic centimeters per minute is also a good consideration for hydroponic air pumps.
- “Effect of high concentrated dissolved oxygen on the plant growth in a deep hydroponic culture under a low temperature” by Suyantohadi, A. et al. in IFAC Journal of Systems and Control.
- “Indicators: Dissolved Oxygen” by National Aquatic Resource Surveys in the United States Environmental Protection Agency
- “The Relation of Algæ to Dissolved Oxygen and Carbon-Dioxide. With Special Reference to Carbonates” by Chambers, C.O. in Missouri Botanical Garden Annual Report