Summer means a lot of fresh vegetables and fruits right from your own garden.
More sunshine doesn’t equal chilly water for your fish.
In this article, I’m going to show a few methods on how to cool the water in your aquaponics system.
Let’s start with pointing out some quick fixes:
Add shade netting
When the sun beats down on your fish tank it will get warmer quicker. Your plants may wilt too because of the heat. That’s why adding a 30% or even 50% shade net over your plants is a good idea. It will cool down the environment.
Having shade netting installed will limit the sun exposure to the grow media in the growbeds. Grow media like clay pebbles can be heat absorbing and may cause the water to heat up rapidly if exposed to sunshine.
Insulate the walls of your fish tank and growbeds
Insulating walls (especially the fish tank) will drastically reduce the heating of the water. Insulating can be done by using rigid insulation panels or straw bales. You can use the insulation again in the winter to prevent freezing temperatures.
Add ice bottles in small systems
This method will require some careful monitoring but is a good short term solution to a rise in temperature. While other measures require time like the insulation or shade netting, adding ice bottles into the water will quickly reduce the temperature of the system.
This only works with small backyard systems. Do not use the ice bottles directly in the fish tank. If you can, put them in the sump.
Do not fill the bottle completely full, this will burst in the fridge. Leave the water a few inches from the top.
Add an evaporate cooler in your greenhouse
By cooling off the air, you can reduce the temperature of the water. This only works in a greenhouse.
In my book, I talk about how to create a cheap evaporate cooler.
Use an underground loop to cool the water
This idea uses geothermal cooling capacity. The idea is that you use a pump to run the water through a tube the is 5 to 10 feet (1.5-3 meters) underground. The temperature at that depth will be 50-73°F (10-23°C). Source
You can use this temperature to run a tube in a ditch and pump it back to the fish tank or sump. The volume doesn’t need to be big because it doesn’t need to travel rapidly through these tubes. You can use a split-flow from your existing pump or use a completely separate loop.
Increase the total water volume of your system
The more volume of water you have, the more resistant it is to temperature changes. Therefore, it is beneficial to increase the volume of your aquaponics system. Deep water culture will have more stable temperatures than NFT because DWC has more volume of water.