Backyard Aquaponics
A place to discuss aquaponics

I'd like to gather some information and ideas, both theoretical and, better still, successful, on cooling fish tanks. Anyone that is perhaps trying to get trout going all year, or, like me, is simply trying to extend the season a month or so. I have a long way to go with my system and I'll need to start with the basic. Shade and insulation first and foremost, but I have seen some more technical set ups on here. If those people would like to share their genius, can we get a description and see some targeted photos and maybe get down and dirty with a sketch program of your choice?

Well this topic has been around for ages.
the system below is used to keep trout all year round...
The earth is used to keep it cool, during this year of extremes here the temp didn't get above 22c
viewtopic.php?f=18&t=5504&start=0

I know someone in W.A., not on the forum, who runs his water through a domestic chest freezer. he reckons it works very well..

Yep... But I was thinking more along the lines of an upfront cost to set up, but without ongoing costs such as power
or possible machinery breakdown.
Passive you might say

Yup, bury everything, or:



Them blue towers are normal evaporative coolers. Even a household unit creates a lot of very cold water.

I was thinking of something like that. If you had a beer fridge and you plumbed a coil into the usually unused freezer section, it wouldn't feel like you had to justify the power use with the system. It is simply cooling your beer so it is a cost you were incuring anyway. Conveniently overlooking the extra power it takes to cool a constant stream of warm water .

The cooling tower concept is where I'm heading currently. Some sort of tall box with baffles in it, sitting on my FT lid. Great minds have already told me I need to be pumping my FT volume every hour, so I should buy a 10kL/h pond pump and the recirculating portion can be run over the cooling tower.

If I am not wrong, massive volume of water is also important...

A smaller bucket of water might be easier to alter in temp, short term.

I'm thinking a small evaporative roof number, sat straight on the lid of my tank. There are only 8 cubes in there if it was empty, let alone 3/4 full. That's less than a toilet (the room, not the bowl). The shaded air would blow down and across the water's surface. I asked around and an air con mob here fix up busted ones when the apprentices have nothing better to do (3 units to make 1 or whatever) and the boss flogs them for a carton. If I found one with no pump, I'm sure there'd be some water to divert to the unit somewhere in the system and it'd only be the cost of spinning the fan that's extra.

Here in the UK we have the opposite problem... trying to keep trout warm during the winter.

But back to your original question, what about a ground source pump? Or the equivalent. If you could bury a large sump tank then the ground temperatures would keep it cool. I seem to remember in another thread somebody buried an IBC to act as the sump. This would probably have a cooling effect on water temperatures.

I'm wondering if the cost involved in digging/burying a larger sump would be comparable to making/running an evaporative cooler.

What about running a series of water pipes in trenches about 18" deep. The temperature of the soil at that depth is fairly constant and would steady the water temperature. Easier to bury than a dirty grreat tank

not meant to hijack the thread, i'll get to the subject.. but..one of the things that i really dig about aquaponics are all of the "low tech" applications of advanced mechanical engineering stuff
my background is civil/structural/architectural/mechanical engineering, but i've moved on to IT stuff, network and server management..

one of my first jobs after getting out of the navy was desiging fire protection sprinkler systems, delivering a presrcibed amount of water to a defined space under a certain pressure.. the possibilities of adapting that to AP make me dizzy..

but speaking of the water temps, i've only seen geothermal mentioned a few times, and have been a part of small to medium size facilities projects that have utilized it.. geothermal will provide a constant temp to either heat or cool with, at lower energy use..
this place make me think to much

The thing with an underground tank is that it has a relatively small surface area or contact area with the dirt, and you need one you can seal as it's probably lower than your FT. On the other hand, a brand spanking roll of 25mm poly can be layed in a deepish but rough hole and loosened as it is back filled, and the 2 ends poking out of the ground at the end should be the only place the water can get out. My maths makes a 200m roll only 98L though.

Hmmm. But the larger quantity of water in a buried sump means that it would be far less susceptible to temperature variations. There are pros and cons to both methods. It is purely dependent on the amount of time, money and effort you are willing to provide.

We're just here to throw as many ideas as we can at you in the hopes that you can see all possible solutions then choose the one which is best for your setup.

A cheap and easy trick might be 400' of 3/4" black pipe run through a wooded area that water is cycled through in the evening. There are is a real nice stand of hardwoods about 30' from my FT that I will run pipe through this Summer to cool water in the evenings...

The idea of trenching or burying a huge coil of pipe should be equally effective. Just cycle water through it as a cooler. A little tiny pump can be used as the cooling will be most effective if the water is moving at a slow speed.

Keith, I agree... The development and use of low-tech solutions is half the fun!!

CB