Backyard Aquaponics
A place to discuss aquaponics

Please help me figure out how to keep cool temperatures for the fish.

Context and climate: I'm planning an aquaponics small-scale commercial operation for the south of France. Temperatures go from an average of 5°C in the winter (with lowest being -10°C to -15°C) to an average of 21°C in the summer (with highest being 36°C to 39°C). In the summer, temperatures can still go as low as 5°C at night.

Requirements and assets: One of the fish I want to raise is Atlantic Salmon. Their preferred temperature is around 13°C. Coincidentally, geothermal temperatures at 4.5m to 10m under ground are around 12°C in this region.

The plan: The main idea so far is to have an underground "greenhouse" with artificial lighting (for the plants) and try and keep it at 13°C. It will sit just below ground level (-1m) for insulation purposes and protection from the sun. Metal pipes will run down to -5m to -10m under ground level and weave at that level before coming back up to the "greenhouse". Fans attached to the inlets and outlets of the pipes will circulate the air, thus cooling down the grow house.

Can you think of a better plan? Will this one work? What tweaks would you add? What am I not thinking of?

You don't have to keep the water at exactly 13C the whole time, and it will probably cost quite a bit to keep it close to that.
Running your AP water through metal pipes, if Copper, or Zinc plated (galvanised) will kill the fish.

Burying part of the system in ground will certainly help stabilise the temps, but running a water chiller in summer, or not keeping the fish over summer might be a simpler solution.

I'm assuming it's legal to raise salmon there as it's not here. Hatcheries can but they have to sell them gutted.
The guys at the local hatchery say they are very hard to rear with many loses at every step of the way. Good luck.

In my experience, Rainbow Trout taste better than Atlantic Salmon raised in the same AP tank

Correct, got six left out of six hundred.


My last six are pets now, couldn't bring myself to eat them.