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I'm screwed, which chiller do you suggest


Pygmy Octopus
Jun 5, 2003
There is basically no way to lower the temp in my tank without a chiller. It is a 30 gallon with a 8 gal sump. It sits at a consistant 88 degrees without a light yet. With the light I'm guessing it will be at 90. I need to get this down to about 75. Do you guys have any suggestions on which chiller to get. I need to keep the size and price as low as possible because I had no idea I was going to need this and I did not plan for it.
Why not try a search for DIY chilers first?

mine was second hand from a water chiller in a drinks dispensor and cost me £20!

have a search on google under DIY aquarium chillers

Phone up some places that hire out water coolers for offices and see if you can get a cheap 2nd hand unit?????? This doesn't need to break the bank!
I used to be into big reef tanks, and investigated chillers from that perspective.

DIY chillers generally don't work. If you use plastic/rubber hose (for example running it through a mini-fridge) you don't get good enough heat exchange. I'd beware of using chillers made for a drinking water dispensor, as it probably has copper tubing in the heat exchanger, and this will likely leach copper into the water over time, killing your octopus.

Real chillers made for salt water use titanium heat exchangers, which is part of why they are so expensive. But you need to use something that won't corrode in salt water (or leach poisonous metals) and passes heat fairly well.

The best solution in many cases is to put a window air-conditioner in the room that houses your tank. That way you don't need something special for aquariums, and you can enjoy the cooling too.

Another solution that I've used a couple of times is evaporative cooling (i.e. swamp-coolers). The idea is to put one or more small fans so that they blow across the surface of the water. If you do this right, and the humidity isn't too high, it will evaporate over a gallon of water a day from the tank, but cool the tank at the same time. Of course, if you have an octopus that likes to try to escape, you have a problem, as you won't get good air flow with a tight fitting cover. I've used computer muffin-fans for this when I've done it. Be warned--they are called swamp coolers because it will make the rest of the room warmer and more humid (swamp-like).

Dont rubbish the DIY aspect just yet as many of the drinks coolers like the one i got are not using copper in the system. It should just be a question to ask when you are phoning about the companies...

yeah the btu of a dorm fridge is too small to cool down a tank but there are other DIY ways like the 'swamp cooler'
I'm using a version of the swamp cooler - a little $10 fan blowing on the sump. I lose maybe 1/4 -1/3 gallon of water a day, but the effect is enough to lower my tank temperature about 4 degrees, which puts it in the low seventies. This amount of evaporation doesn't make the room too humid.

We have central air conditioning, but on these very hot Texas days the house gets a degree or two warmer than usual, so I have been putting an ice cube or two (made from distilled water) into the sump as well.

So I think do it yourself can be effective.


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