Best Water Chiller for Hydroponic Reservoirs Choose the Right Size for Your System

Plants are living beings, like people, they want to be comfortable. With hydroponics, you worry about the light, humidity, and temperature above the growing zone.

What about the roots below?

They need to be comfortable too. Keep them that way with a Water Chiller. This odd sounding machine does just what it says it does, chills the water.

Hydroponic systems can create a lot of heat, which transfers to the water nutrition system. As we will see, that is not always a good thing.

Why Would You Need a Water Chillers?

Heat from the lights will warm everything up. A water chiller will keep the root system cool. The ideal water temperature at the rootzone is 65-70 degrees Fahrenheit.

This range allows higher levels of dissolved oxygen to be accessible to the root zone. Also, it strengthens plant disease suppression.

As temperatures in the nutrient solution rise, the ability for it to hold dissolved oxygen diminishes. This reduces the amount of oxygen available to the root zone.

You then get slow growth and poor plant performance. With warm water temperatures and lack of oxygen, serious diseases such as root rot and damping-off can occur.

How it Works

Water chillers work with your water pump. Circulating the nutrient solution through your system and through the water chiller. It goes over cooling coils and chilled to the desired temperature. The cooled solution then circulates back into the system.

Pros and Cons of hydroponic chiller

The pros are obvious. Cooler temperatures increase quantities of dissolved oxygen. Creating better root growth and increased nutrient uptake.

It deters diseases that can overtake your system. The cooler solution will also lower the temperature in the room that you are in.

The cons are something to consider. Water chiller equipment creates heat. They should be outside of the room you are growing in or create an exhaust system to get the heat out.

They tend to be pricey. Technology is getting better, but it is still considered a large investment. Certain water chillers will be noisy.

Technology is getting better, but they are still loud. Depending on what type of system you have.

Types of Chillers you can use

Drop in water chillers go direct into the water filters. For deep water hydroponics, this is the best for you. It is easy to install and doesn’t take up too much space.

Thermoelectric Chillers are best for smaller hydroponic systems. Largest water level being 55 gallons. This system does not produce any vibrating sounds when working. Considered the most cost-effective. This is due to the low-maintenance upkeep when compared to the other systems.

The in-line water chiller is for larger systems. These need plumbing of the in-line filters. They come in 1/4 to 1-ton sizes. This is the best water chiller to use for a nutrient film technique system.

What size water chiller do I need for my hydroponic system?

This can be a very complicated question, but also very important. To start, it’s vital to know the size of your reservoir. Then you use some computations to know what size chiller you need.

As close as possible, figure out how much water is in your hydroponic system. Then, during the hottest part of the day, turn everything on that produces heat. You want to get the room up to the highest normal temperature possible.

Using sealed bags of ice or frozen two-liter bottles, cool your system down to 65- or 70-degrees Fahrenheit. When it gets down to the right water temperature, take out the ice and start circulating the water.

Take note of the actual starting temperature. Wait one hour, then check the current temperature. Subtract your 1-hour temp from your starting temperature. This will be your temperature differential.

Then, calculate the BTUs you need:

Gallons of Water in your reservoir X 8.34 (the weight of a gallon of water) X your temperature differential

Now you know how many BTUs you need to chill your system.

Here is an Example Calculation

If you have a 75-gallon system and your max temperature was 80F. You want the temperature to be 65F, and after an hour the water temperature was 70F.

75 X 8.34 X 5 = 3,127.5 BTU’s

The standard sizes that water chillers come in are,

  1. 1/10 ton = 1,200 BTU’s
  2. 1/4 ton = 3,000 BTU’s
  3. 1/2 ton = 6,000 BTU’s
  4. 1 ton = 12,000 BTU’s

So, as you can see by our example, you should get a ½ ton because the rated BTU’s are never what they say. Give yourself some extra leeway.

Other Ways to Chill Your System

As mentioned above, you can use ice or frozen bottles of water. This is time consuming and can be inaccurate. Larger systems would need too much ice. Paint your reservoir and everything else white. The color white reflects light, which reduces heat absorption. Light energy converts to heat.

What Are The Best Water Chillers For Hydroponics?

As mentioned above, it will depend on many variables as to which size and type you should get. This list consists of some of the better ones of various sizes.

IceProbe Thermoelectric Water Chiller

If you have a system that is 55 gallons or less, this is top of the list. It is powered by electricity but is guaranteed zero noise during operation. Energy efficient saving your money on electricity. It works well with other parts of your hydroponic system such as the pre-filters, siphon overflows and others.

It is ideal for small hydroponic systems, durable, and comes with a one-year warranty. The one downside to this chiller is, it does not have an on/off switch.

It provides continuous chilling when plugged in, you need a separate temperature controller to turn the device on or off at pre-determined temperatures.

JBJ Aquarium Arctica Titanium Chiller


Named one of the best water chillers on the market because of its durability. It has an LED display control that allows you to see the temperature at night. It cools 120 gallons of water in little time. No temperature fluctuations, the water is kept at a consistent temperature.

It has a two-year warranty. Considered eco-friendly by using a refrigerant called R-134A. Easy to install and use. Recommended for beginners. While a tad on the pricy side, the company stands behind its products.

EcoPlus Commercial Grade Water Chiller

This monster is for those of you with big hydroponic systems. Cools 300 gallons of water in short order. Suitable for use with reservoirs, hydroponic systems & aquariums. Comes with a commercial-grade titanium heat exchanger.

Designed for optimum performance and corrosion resistance. Reliable compressor, efficient, and durable. It has an easy to read LCD display. Temperature memory with auto restart in case of power outage.

Temperature controller is on a 30-foot cord, so device can be installed outside of your growing area. The unit must be plumbed with 1” hard PVC pipe or 1” flexible tubing. Obvious disadvantage to this one is price.

In Conclusion

Getting a water chiller for your aquaponic system is an investment. Make sure you do your homework on size and type. Every system is different and requires different maintenance.

The best recommendation for getting the correct size chiller is to visit the manufacturer’s website.

Follow any and all manufacturer’s instructions on installation and cleaning. Once up and running, your plants will be the beneficiary of a comfortable life.

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Lindsey Hyland grew up in Arizona where she attended University of Arizona’s Controlled Environment Agriculture. She has supplemented her formal education by working on various organic farms, including spending a semester abroad in India.

Growing and/or raising just about anything gets her excited. She is especially passionate about environmental justice and low-tech, sustainable ways to better run small-scale farms and homesteads. Lindsey started Urban Organic Yield to discuss gardening tips and tactics.

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