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Is Dissolved Oxygen the Key To Healthier Plants?

Date: 15-12-2021

Let’s get started with the basics. What is dissolved oxygen and why is it so important? 

Dissolved oxygen (otherwise called molecular oxygen) does the same job as regular old oxygen - with the major difference being it’s used by aquatic life and the aerobic organisms living around your plant’s root zone. 

For this reason, the quality of your water is based on it’s dissolved oxygen content. More dissolved oxygen = better quality water. 

So, why should you care about this?

The beneficial organisms working to keep your plant’s rhizosphere healthy need dissolved oxygen to survive. 

The consequence of removing too much dissolved oxygen is that these beneficial organisms will begin to die - fostering a perfect environment for anaerobic and pathogenic organisms like pythium. 

In fact, almost every pathogenic disease related to your plant’s root zone could have been avoided with more dissolved oxygen!

Another benefit of highly oxygenated water is that it regulates the availability of certain nutrients. Studies have even demonstrated that the number of nitrifying microbes increases alongside dissolved oxygen levels. 

Now you know how important dissolved oxygen is, how you can improve the quality of your water supply so that your plants are getting more of it?

There are two main physical factors that affect dissolved oxygen and the good news is that you can control them both. They are salinity (salt) and temperature. 

We’re going to focus on temperature because by the time your system contains the level of salt needed to affect your water’s dissolved oxygen content your plants will be long past showing signs of toxicity (they’d be dead). 

Temperature on the other hand can quickly become an issue for your dissolved oxygen content. Heat is the enemy which means as temperature increases, dissolved oxygen decreases. 

Living in Australia makes it all the more important to keep temperature under control because the weather is working against you. If you’re an indoor or hothouse hydroponic grower, you may also have grow lights to contend with as these are certainly adding heat to your grow room. 

The takeaway from this info is that you need to be cooling your water down. 

There are a couple of ways you can do this. Here’s what we recommend: 

The most popular way to cool down the water in your tank or reservoir is with the help of a water chiller. We really like the Hailea HC100A. 

A water chiller is a great option for hydroponic and aquaponic growers alike, however, if you grow using aquaponics you’ll need to consider the ideal temperature for your fish. Some fish, like barramundi, prefer temperatures ranging from 25 to 30 degrees. In this case, adding a water cooler will do more harm than good. 

If you’re not sure whether your fish can handle a reduced temperature, give us a call. 

For hydroponic growers, a water chiller allows you to maximize dissolved oxygen without compromising the ambient temperature of your grow room, as this needs to be a little higher for CO2 enrichment. 

Running a submersible pump in your tank also creates unwanted heat which you can combat with a water chiller. 

Another effective method for improving the dissolved oxygen content of your water supply is through aeration. You can do this by adding an air pump and stone to your reservoir or tank. If you’re growing in coco peat aeration can be achieved by adding another hydroponic medium such as perlite.