How Do Aquarium Chillers Work&mdashDo You Need One

How Do Aquarium Chillers Work&mdashDo You Need One

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Keeping a tropical fish tank warm is pretty easy since aquarium heaters are readily available and quite affordable, but what do you in summer (or during a heatwave) with temperatures threatening to boil your tank, and kill your aquatic animals.

Well, that’s where aquarium chillers come in, but you may know this already, yes😃?

The more pressing question is how do they work, are they worth your hard-earned buck, are they even practical?

The most uncomplicated way to look at aquarium chillers is more like a fan for your fish tank that works reverse of a heater. Meaning, when the water temperature gets too high, they bring it down and keep it within the sufficient range for your fish.

Chillers come in handy in some situation and can be worth your buck, but they are not a must, particularly while maintaining freshwater fish. Unless of course, if you live in a region with bipolar weather, where summers are sizzling hot, and the winters freezing cold.

What is An Aquarium Chiller

I’ve already mentioned a chiller is used for cooling water in a fish tank, or at least, keep the temperature from rising too high.

I’ve also stated it works against the grain of an aquarium heater.

Even so, this logic is at best a layman interpretation because the two pieces of equipment are made differently, and while both will manage the temperature in your aquarium, chillers are arguably more complicated than heaters.

As such, think of an aquarium chiller as a small refrigerator, which is most times installed in-line with an external aquarium filter to cool (or chill) the water as it passes through the system.

When equipped with a thermostat, your chiller will go a step ahead and keep your water from rising above a pre-set temperature, which is helpful when you own fishes like goldfish that prefer things on the chiller side.

Once you get to buying a unit, you’ll also note that there are several types, and depending on your tank’s size or the temperature of where its located, one design might be more suitable for you as opposed to the others.

Thermoelectric chillers are best for small freshwater and saltwater tanks that are less than 55 gallons.

Compared to the other types, these chillers are easy to install and run relatively quiet. Typically, a probe is placed in the water along with a fan which dissipates the heat.

In line chillers, which are ideal for larger saltwater reef tanks, are usually incorporated into the filters pipework and cool the filtered water before its flows back into the aquarium.

Drop-in chillers are an ideal alternative for in-line units mostly used in saltwater tanks with a coil that sits inside the sump. They are perfect in case you have limited space for in-line style chillers.

Drop in chillers also come in a variety of sizes.

How Aquarium Chillers Work

The principle of operation of most aquarium chillers are a lot like those of a refrigerator. Basically, they use compressed vapor (gas) to remove heat from your fish tank water and carries it to a radiator where a fan ejects it from the system.

The intricate physics maybe be complicated and differ from one unit to another, but this principle pretty much remains unchanged.

The chilling process starts with the water getting into a heat exchanger where it flows through a series of cold metal coils filled with refrigerant.

All around the coils, heat leaves the water into the refrigerant, which then takes it to a condenser where a fan blows air over the chiller cooling the ‘warm-refrigerant’ and expel heat into the atmosphere around the system.

With most chillers, a controller monitors the temperature of your aquarium water and automatically switches the unit ON when the settings rise above a pre-set mark.

The same controller will also turn the chiller OFF when the temperature cools down to the desired level.

How Cold Do Aquarium Chillers Get

How much a chiller cools an aquarium depends on its rating.

Usually, this is in reference to the size of your fish tank and degrees of temperature the unit will need to lower given specific dimensions.

For instance, you can have a 1/15Hp unit with a maximum chilling capacity of 50-gallons at 10℉ below the average room temperature (68℉ to 72℉), though the same equipment could reach 20℉ below the ambient atmosphere in a 30gallon tank within the same period because of the smaller load it has to cool down.

That said, please note that most chillers work on being able to cool the water by up to about 10℉ below room temperature; for it’s recommended volume.

So to buy the perfect chiller, make sure you know the dimensions and size of your aquarium and the temperature that needs to be brought down to keep it at an optimum level.

How to Size an Aquarium Chiller

Given the background above, sizing your aquarium chiller (see different sized chillers) should not be too complicated.

Manufacturers will usually recommend the maximum aquarium size that a chiller can be used on, though I’d suggest going slightly oversize to ensure your tank is cooled efficiently.

However, do not go too high because although bigger chillers will cool water faster, they also have a more active flow which you will have to adjust.

Usually, the capacity will be indicated on the packaging, manual, or product description when buying a chiller online. You should be able to assess the max aquarium size, temperature range, and even price range.

Laslty, you will see Horsepower (abbreviated HP) or British Thermal Units (abbreviated BTU) on aquarium chillers quite often. But not to worry, the measurements units are just used to describe the amount of energy required to change one pound of water one degree of Fahrenheit.

Like aquarium filters, chillers are rated using the volume of water they can cool efficiently. Using a chiller that is not large enough for your tank will mean the unit may not be able to cope with lowering the temperature to the level you require.

Why Are Aquarium Chillers So Expensive

I don’t know about you, but part of the reason I needed to understand how aquarium chillers work is to gauge whether the more than prohibitive price tag sellers demand is justified🤔.

As it turns out, it just might be😒!

Apparently, chillers are so expensive because they are niche refrigerators. In other words, they are a generally pricey piece of electronic, with the expense compounded by their unique nature that’s shy of mass-production.

Most units come with the whole refrigeration shebang; the entire compressor-decompressor and big-radiator thing going on, and a few electronic bits to monitor temperature.

Furthermore, the specific heat capacity of water is much higher than that of air, plus many fish tanks are not insulated, meaning it’ll take a lot more energy to lower the temperature in your aquarium.

As such, aquarium chillers often have to work both harder and run more often than refrigerators. Of course, this comes with an extra cost of production, which is then transferred to the end-user.

One other thing that might explain the cost is the supposed use of titanium in the workings and pipework to keep your chiller parts from getting damaged by salty water.

Which sounds pretty plausible, but don’t quote me!😜🧐

Good aquarium chillers use high-quality refrigeration units that can work continuously. Also, a fridge cools something down and then really maintains that temperature. A chiller, on the other hand, ends up having to switch in a continuous cycle to extract heat from tank water.

Do You Need A Chiller For Your Aquarium

Considering aquarium chillers are quite pricey (justifiably so), its not uncommon to wonder whether you really need to have one in your fish tank.

Luckily, it is not a must, in fact, most tropical fish tank owners rarely use them.

Even so, aquarium chiller do come in handy in some situation and are quite useful for people living in some regions of the world than others.

You may need a chiller for your aquarium if you live in a zone where the temperatures can reach prohibitively high numbers.

This is especially true in many Southern states of the USA including Texas, Arizona, Nevada, and California, and in countries like Australia where the summer temperature can easily top 110℉ , and stay above 90 at night.

Such spikes can be too much even for hardy tropical fish, especially if the readings persist or keep fluctuating.

The other factor to consider is the location of your fish tank.

Take a fish tank in the basement, garage, or attic during the formerly stated summer weather in Southern California. If for some reason you also need to leave your hood lights on, your water would be boiling, fishes struggling to stay alive, and an aquarium chiller a very welcome accessory.

That said, aquarium chillers are more necessary in saltwater and reef tanks as opposed to freshwater aquariums since tropical fish are quite hardy and adaptable.

However, make sure you understand the preferred temperature of the tropical species you have. You do not want to have something like a goldfish or other cooler water fish like danios and white clouds in a tank with no chiller (cooling mechanism) on a hot summer day.

Because aquarium equipment, particularly those used in reef tanks, produce a lot of heat, many hobbyists need an aquarium water chiller. Though some aquarists get by with fans which cool water through evaporation.

How To Cool Down Your Aquarium Without a Chiller

Chillers are pretty good equipment for lowering your fish tank temperature, but they do cost a lot, meaning you may need to do a little of saving to get one.

But that does not mean all is lost, there are still a couple of things you can do to keep the temperature in your tank within the desired level for the fish you have.

Most hobbyists go for fans as they are quite efficient, almost like chillers, especially if the temperature has not risen too far. But you can also use any of this other tricks.

  • Use a cooling fan: Blower style, Tower style, Exhausr fan, massey clip fan
  • Use ice packs or cold water bottles
  • Turn off your lights and open the hood
  • Relocate your fish tank
  • Use an air conditioner

#1&mdashUsing Cooling Fans

Installing one or multiple aquarium fans will go a long way in cooling your fish tank.

A fan will blow air across the surface of your water cooling your tank through evaporation, and keep your lights from overheating as well.

Thats said, you want to make sure you use an appropriate size fan for the fish tank you have, but you are not limited on the types and design of a unit.

Blower style, tower-style, exhaust, and Massey pin fans will all work, but when looking for something designed specifically for use in a fish tank, consider this cooling fan unit; available on Amazon.

#2&mdashUsing Ice Packs and Cold Water Bottles

During emergencies without much time to source for a chiller or cooling fan for an overheating fish tank, ice bags, and cold water bottles can come in handy even if temporarily.

The trick is quite straightforward, you only need to keep in mind that it only works for a short time because the heat in the fish tank will gradually melt the ice.

As such, to keep your tank cooler for longer with ice pack or bottles, be sure to prepare a couple of them adding each at a time.

Moreover, beware that the melting ice might find its way to your fish tank, so ensure the base products used to produce it is safe for your fish tank.

#3&mdashTurn Your Aquarium Lights Off

Part of the reason your fish tank is a furnace might be due to residual heat from your lights especially when coupled with a hood which limits cooling by evaporations.

For that reason, turning off your aquarium lights and moving the hood when not in use or necessary is another effective way of keeping your tank chill.

Depending on the type of lights you have, changing them to a unit that does not produce too much heat might be an ideal longterm solution.

Essentially, LED units (see recommended product) produce almost zero heat and are best for use in aquariums especially with overheating issues.

#4&mdashRelocate Your Fish Tank

One last hack that works quite well, especially in a house with air conditioning is moving your fish tank to a place with good air circulation.

Aquariums near window seals and with direct access to sunlight is typically ideal when growing live aquarium plants, but the light from the sun tend to overheat the water.

Therefore, in times of warm weather and heat waves, you will want to move such tanks in a more shaded space, particularly in areas with good air conditioning.

The closer you can get your tank to your room air-con system, the better. Even so, please confirm the setting of the air conditioner because you might end up heating your tank furthers instead of chilling it.

Thats all, happy fish keeping.

Eddie Waithaka

Resident Content Creator and Marketer at AquariaWise who talks about aquariums and fish and aquascapes a lot.

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