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IBC Fishtank Cooling System?

Good morning! We have an IBC that we're going to use for our fish, but the water in it is currently in the high 80s/low 90s. I'm afraid to put the fish in there, especially when we have another heat wave like earlier this week. How are you guys keeping your fish cool? We have about 50 bluegill currently residing in a fishtank indoors . . .

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Permalink Reply by Richard Bunch on July 17, 2014 at 12:59pm

You might want to build a plywood enclosure for your tank with a plywood lid. It will preserve the plastic from the sun's damaging rays and keep it cooler.

Permalink Reply by Tom Hack on July 17, 2014 at 3:09pm

Jennifer,

I am located in Roseville and I have no problems with my water temp in fact I think that my fish tank water is cooler than the average un-heated swimming pool. I am not using IBC's as I had to make my system look nice to appease the wife. My system consists of cinder blocks that are lined first with foam insulation and then with Durascrim liner. It also has underground plumbing and has grow beds shading the fish tank.

The advantage of this is that the ground acts as a heat sink and cools the water in the summer and warms it in the winter.

My suggestion is to insulate your fish tank, get it shaded and get any exposed plumbing out of the sun. If you are using NFT pipes then those will heat your water.

Cooling options- build a chiller using a freezer or bury a line as the average temp 1-2 feet underground is cooler.

Permalink Reply by Paul Trudeau on July 18, 2014 at 6:32am

Hi Jennifer,

I've been using bluegill in my systems in Sac for the last few years and high temperature has not been a problem. I shade the tanks as much as possible. Bluegill should be fine up to 90 degrees, with average growth up to 85 degrees and optimum 80 degrees (per "Aquaponic Food Production", Rebecca Nelson). They might tolerate occasional temps higher than 90 too. Also, it's my understanding that temperature stability is important. That is, fish should tolerate fairly extreme temperatures more easily if the temp doesn't fluctuate wildly. They are more likely to have problems with big temperature swings, which is why you'll sometimes see more fish deaths in spring or fall when temperatures are more volatile. In fact, the only time I had a problem with my bluegill was during a big temp swing in spring one year, combined with plumbing failure.

As you probably know, warmer water holds less oxygen. So it's good to build splashing into your system wherever possible and plenty of air bubbling through especially when it's warm. And keeping your fish density low helps.

I like all of Tom & Richard's suggestions except for building a chiller. Cooling water electrically is very energy inten$ive. On the other hand, theoretically you could use a reconfigure a solar water heater to act as a chiller, radiating heat to the air rather than gathering heat from the sun, but I'm not sure it's worth the trouble.