Beginner Must Know - Do I need an aquarium chiller?

What is the purpose of an aquarium chiller?

To chill the water in an aquarium. Read below why some fish need this. Although I mention fish only, corals or live rocks need stable temperature too. And some freshwater plants are sensible to dramatic temperature changes too.


Do I need an aquarium chiller?
Well... It depends on the type of your aquarium. If it’s a marine fish tank, then it is very likely that one needs a chiller. This results from the fact that saltwater fish live in waters with very stable temperature (unlike freshwater species). Unless you live in a country where the average yearly temperature stays below 20°C (even in rooms; which is not likely), it is not necessary to buy an aquarium chiller.

The second possibility when one needs a cooler is a coldwater fish tank. Some fish species (especially small ones) from rivers can be kept in home fish tanks, or in fish ponds. Naturally, it is hard to imagine a chiller connected to a garden pond. Back to aquariums... Fish from rivers are accustomed to temperatures of 5 to 20°C, sometimes more. In order to maintain the temperature within some acceptable interval, any such aquarium cannot be without a chiller.

The third situation when a fish tank requires a chiller’s help is too hot temperature (usually during Summer). I won’t discuss this point since it is clear that any fish tank requires help when the temperature exceeds 30°C. If you cannot afford a chiller, you can use chilled water (put a bottle into the regrigerator), ice, or darken the room.

Related questions
Do I need an aquarium chiller for tropical fish?
Tropical fish don’t require cold water, however temperatures higher than 30°C can cause serious problems including death. It is also necessary to realise that the higher temperature in the aquarium is, the less oxygen is present in the water. With the same aeration there is much more oxygen in a fish tank when the temperature is 20°C than when it’s 27°C!

Do I need a chiller for a cold water aquarium?
Yes, this has been already answered above.

Do I need a chiller for a reef tank?
Yes, this is also answered above.

Is chiller important for a saltwater fish tank?
Yes. As it is mentioned already, marine fish live in very specific conditions where the temperature, pH and hardness change much less than in freshwater environments. Any dramatic and sudden change may affect marine fishes, and thus they can even die. So yes, a cooler is very important for a marine aquarium!


How much does an aquarium chiller cost?
I have seen some from $100 (the cheapest) up to $1400 (probably even more; the most expensive on the market). Here is a link which should help you to find one: google.com/products?q=aquarium+chiller&btnG=Search+Products&hl=en&show=dd (the link did work on 29/10/2008, contact us if it doesn’t work any longer, please). Before you buy any, ask the seller about chilling as some smaller (usually characterised by lower wattage) chillers cannot cool the water enough. Then more units are needed to achieve the same effect as a bigger one could do easily.

How do I setup/install an already bought chiller?
It’s good to place a chiller somewhere to an open place due to ventilation. Otherwise it is hard to tell you some “general rules” due to uniqueness of each product, although they operate on the same principle. Always follow the guidelines provided by the manufacturer.

Do Goldfish require an aquarium chiller?
Yes. They’re coldwater fish and unless you want to keep them unhappy, don’t buy a chiller. Moreover, goldfish should be kept in garden ponds rather than in home fish tanks.

Does Axolotl need an aquarium cooler?
Not necessarily. According to an already existing article on Aqua-Fish.Net (this one : aqua-fish.net/show.php?h=axolotl ), these beings lives in environment where the temperature varies between 10°C and 22°C, however sometimes it is even lower than 10°C. Therefore if you’re sure that 22°C is the highest possible during the whole year, then your aquarium doesn’t need a chiller.

What is the principle of how an aquarium chiller works?
First, the water is pumped through the heat exchanger, where the cold compressed gas flows. This compressed gas is there in order to pick up the heat from the water in an aquarium. The heat is taken back to the compressor and the pressure drops. Finally, the heat is taken to a radiator. A fan sucks new air and lets the hot air go out of the chiller. This is taken from another article on our website: aqua-fish.net/show.php?h=aquariumchillers.

Is there a way how to chill an aquarium without a fish tank chiller?
Yes. As it is already mentioned above, darkening the room helps the most. Sometimes this is not sufficient. In such a case do daily water changes and add cooled water into the tank. I found adding ice to be a very useful method to make water colder. About 20 cubes (each of 1x1cm) of ice lowered temperature in one of my aquariums (42L) from 30°C to 27°C immediately. This, however, also depends on how long has been the water in the freezer. The longer, the better effect in the end.

Do aquarium chillers run all the time?
It is possible to run them non-stop, however it is not recommended. It’s like a refrigerator; They don’t chill all the time (it is automated, naturally).

How big should be a fish tank chiller be?
The size doesn’t matter. It’s all about wattage and output, and flow rate. For example, compare these two chillers:
Pacific Coast CL-85 micro chiller
1/4 HP Oceanic Aquarium Chiller


The first one’s output is 85 watt. 80-160 Gallons per hour is the optimal flow rate. The dimensions are: 4" x 4 3/4" x 7 1/2" . The second one’s flow rate is between 475 and 800 Gallons per hour. The dimensions are: 13 x 17 x 17.31 . The difference should be clear. The more gph, the more wattge and space.

What is the best chiller for aquariums?
Although I don’t want to prefer any manufacturer, Oceanic seems to be very good. However, even Mercedes-Benz sometimes produces a car that shows problems after being used. Make your decision based on available funds, warranty, and availability.

What are pros and cons of an aquarium chiller?
Advantages:
Chillers make the temperature stable with no effort. This results in happier fish. Please look at the beginning of this article to understand why some fish simply need a chiller.
If you’re going on a vacation, you don’t have to worry about overheating your aquarium(s).

Disadvantages:
If there is a failure, you should better have a backup chiller (this can be expensive depending on how many fish tanks you own)
Wattage doesn’t have to be the best. Consumption can be a serious problem if you’re keeping fish only as a hobby (more tanks with chillers = more investments).


Can a frozen water bottle act as chiller in a fish tank?
Yes! But for limited time only. It is already mentioned above as a way of using cheaper solutions than buying coolers.

Is it cheaper to run an air conditioner or a fish tank chiller?
This depends on the room and the amount of aquariums, but also on the size of aquariums. If you need to chill only a one fish tank, then an aquarium chiller is better. From what I know air conditioners usually need at least 1KW/h. If you had 10 small aquariums, then buying 10 chillers wouldn’t be wise since their price + their energy consumption will be higher than if you bought an air conditioner only. I recommend you to calculate this equation:

cost of air conditioner + energy consumption of such conditioner = x
cost of chillers + energy consumption of such chillers = y

If x is bigger than y, then it is better to buy chiller(s). Otherwise buy an air conditioner. Also bear in mind that each air conditioner operates for a limited space. So if a room is 10x10 metres big, then it is usually needed to buy at least 2 air conditioners to chill the air to the desired temperature.

How to get a discount when I buy a chiller?
It’s so easy; Ask for it! I mentioned it already a few times on this website. When you’re buying a thing for more than $200, ask for better price! Do not hesitate, it’s your money.