Aquarium thermometer is an important part of an aquarium temperature controller

5 Best Aquarium Temperature Controller Options

Keeping an accurate water temperature in your aquarium is challenging, mainly because most fish species need a very precise reading that’s typically above room temperature. To make matters more complicated, even minor temperature fluctuations that are common from heaters can cause fish stress, leaving them prone to infection, disease, and even death. Using an aquarium temperature controller can keep your fish at the ideal temperature and reduce your stress.

Aquarium temperature controllers solve the problem by accurately monitoring temperature readings and cycling your heaters on and off to maintain comfortable, healthy water for your fish. Our favorite aquarium water temperature controller is the Inkbird ITC-306T Temperature Controller. We put together the below reviews to help you choose the best aquarium temperature controller for your tank.

Recommended Aquarium Temperature Controller Options:

What is the Best Aquarium Temperature Controller?

Our top recommendation for a single-stage option is the Inkbird ITC-306T Temperature Controller. If you want the most safety measures possible to protect expensive fish or corals, we recommend a dual-stage controller. In that case, we suggest the Inkbird ITC-308 Temperature Controller. Either Inkbird Controller is a great way to go.

What is an Aquarium Temperature Controller?

An aquarium temperature controller is a standalone unit that monitors temperature and cycles separate heaters and chillers on and off. Through this process, it helps to maintain a precise temperature in your tank.

How Does an Aquarium Temperature Controller Work?

Aquarium temperature controllers consist of three main parts that help accomplish temperature regulation.

The temperature sensor probe is placed in your tank, where it reads the water temperature. The sensor sends the information to the second piece, the controller, for analysis. Depending on the settings you’ve dialed into your controller, it will determine if the water is too hot, too cold, or just right.

Depending on where the actual water temperature stands in relation to your settings, the controller sends power to a socket. If you have a single-stage controller, your water heater will be plugged into the socket and will be activated to heat the water. If you have a dual-stage controller, power will be sent either to the water heater socket or the water chiller socket to adjust the temperature up or down, respectively.

Why Do You Need an Aquarium Temperature Controller?

Simple tank setups often include a single water heater, which is sometimes sufficient. However, there are two primary problems with aquarium heaters that can be detrimental to your fish.

First, your fish tank heater can fail and leave your water unheated. Water rapidly loses heat to the surrounding air. As such, if you aren’t regularly checking your aquarium thermometer to ensure the heater is working, you may find the water dropping to dangerous levels and subsequent temperature changes that could kill your fish or leave them prone to infection. Temperature controllers typically include an alarm that will alert you if your heater fails.

Aquarium with aquarium temperature controller

Second, the thermometers in water heaters regularly fail and can cause your heater to stay on even if the desired temperature is exceeded. This often leads to excessively hot water that kills your fish and other tank inhabitants. Temperature controllers have more reliable monitoring systems and cut power to your heater entirely to prevent cooking your tank. Using an aquarium heater controller can stop this sad situation from occurring.

How to Choose an Aquarium Temperature Controller

Not all temperature controllers are created equal. When you’re making your decision, make sure to pay attention to the below factors, as these can ensure you choose the best one for your tank.

1. Watts

Although your temperature controller won’t directly be heating or cooling your water, it will pass power to your heater and chiller. As such, you’ll want to ensure that the controller you choose is more than capable of powering your equipment.

We recommend checking the wattage on your heater and chiller before committing to a temperature controller. It’s best to choose a product that can supply more than enough power for each unit to prevent overloading the controller.

2. Single-Stage or Dual-Stage

Temperature controllers come in two options: single-stage and dual-stage. Choosing the right kind for your aquarium can save you money, time, and frustration.

Single-stage controllers have just one outlet to which they supply electricity. You’ll plug a water heater into the outlet in most cases, and the controller will cycle it on when the water’s actual temperature drops below your desired setting. It will stop sending power to your heater when the upper limit is surpassed.

Single-stage options are sufficient for most freshwater setups, and especially for fish that can stand some minor fluctuations in water conditions.

Dual-stage controllers have two outlets: one for a heater and another for a chiller. Dual-stage options allow for extremely precise temperature settings, and they help prevent temperature spikes in both directions.

Dual-stage controllers are ideal for more expensive setups, especially saltwater tanks that contain expensive fish or corals. They’re also the better option for temperamental fish that don’t do well with small temperature swings.

3. Saltwater or Freshwater Tank

Your water type can help determine which temperature controller is right for you. Saltwater is corrosive and may lead to the gradual degradation of your temperature probe. You’re better off with a controller designed for saltwater that has an anti-corrosion seal over the probe. Additionally, dual-stage controllers are generally better for expensive saltwater tanks, as they prevent dangerous temperature swings in both directions.

Most controllers are suitable for freshwater tanks and won’t corrode in them. However, many aquarists opt for the cheaper single-stage temperature controllers for freshwater tanks. Single-stage options save money and are generally suitable for cheaper, less temperamental freshwater inhabitants.

4. Cooling Option

If you’re an aquarist who enjoys having total control over your tank, you may want to opt for a dual-stage controller that allows you to use both a heater and water chiller.

The two-way temperature control may be overkill for some tanks, but a cooling option is great for those looking to maintain precise tank temperature for the healthiest fish possible.

5. DIY Skills

It is possible to make your own temperature controller. You can purchase the pieces separately and assemble them, building the unit specific to your tank and your needs. If you have the skill and knowledge, you can add multiple temperature probes and take an average reading across your entire tank, you could set the alarm to sound and even text or email you if the temperature range is breached, and much, much more.

Most of us aquarists don’t possess these skills, so a pre-wired controller that most accurately suits our needs is typically best. However, nothing beats a fully customized controller, provided you can wire and install it safely without risking death or injury to yourself and your fish.

6. Price

Aquariums are expensive, so the price of the equipment you add to your setup is always important. When you’re choosing a temperature controller, we recommend getting one with all of the features you think you’ll need while staying within a fixed budget. Remember to factor in the price of your heater and chiller if you don’t already have them, as a temperature controller won’t do much for you without them!

Benefits of Using an Aquarium Temperature Controller

Aquarium temperature controllers help keep your fish safe and give you some peace of mind. There are three primary benefits to using a temperature controller in your tank.

You Won’t Cook Your Fish

A submersible heater in your tank sits underwater constantly, and the humidity can quickly ruin the included temperature sensor, leaving the heating element without a maximum setting. Unfortunately, many aquarists fall victim to a broken water heater and come home to find that they have cooked their fish.

An aquarium heater controller sits outside your tank and is far more reliable in its temperature readings. It ensures that your heater will shut off if the water gets too hot, thereby preventing deadly temperature spikes.

Consistent Temperature Control

Not only are the temperature probes on a controller more reliable than the thermostats included in a water heater, but they’re more accurate. Even expensive heaters don’t always maintain the temperature you set, so using once properly takes some getting used to, regular temperature checks, and adjustments.

Temperature controllers can be tuned to take accurate measurements and cycle your heater and chiller on and off to maintain very precise temperatures. The best controllers can be set to increments of 0.1 degrees.

Audible Temperature Alarm

If a standard water heater fails, you won’t know about the malfunction and resulting water temperature spikes until you check the temperature. Controllers have alarms that alert you with audible beeping anytime a heater or chiller fails and leaves your water outside of your set parameters. This allows you to replace the equipment or make adjustments to keep your fish happy and healthy in the event of a failure.

Best Aquarium Temperature Controller Options

We’ll provide a brief list of our favorite options, followed by in-depth reviews of each to help you choose the best controller for your tank.

Aquarium Temperature Controller Reviews

Our All-Around Recommendation: InkBird ITC-306T Temperature Controller

This is a single-stage controller that is exceptionally reliable. It feels like it will last for many years, and we never had any issue with it failing to cycle power to maintain temperature.

It includes an audible alarm to alert you if your desired temperature parameters aren’t met, which offers some peace of mind.

It’s effortless to set up and tune for your tank.

The temperature probe will corrode in saltwater, but InkBird sells inexpensive replacements that will stand up to corrosion.

It is very affordable and provides excellent value for the money.


  • It is made of durable materials that will likely last for years
  • It includes an accurate temperature probe for precise measurements
  • It includes two screens to show current and set temperature


  • It’s very affordable
  • It includes an alarm that alerts you to low temperatures
  • It’s straightforward to set up


  • It doesn’t include an outlet for a chiller
  • You’ll need to buy a separate probe for saltwater tanks

All-Around Alternative: InkBird ITC-308 Temperature Controller

This is InkBird’s dual-stage temperature controller, so it has two outlets for both a heater and a chiller. It can maintain very precise temperature settings to 0.1 degrees.

It includes two LCD screens to display the actual and desired temperature simultaneously. The controller has an audible alarm to alert you if the water conditions fall outside your set parameters.

This product is very affordable, and it offers excellent value for the money. However, you will need to factor in the cost of an anti-corrosion temperature probe if you have a saltwater setup.


  • It includes two LCD screens to show actual and desired temperatures
  • It allows for precision to 0.1 degree


  • It is very affordable
  • It can supply power to both a heater and a chiller
  • It includes an audible alarm for temperature spikes


  • It’s slightly more expensive than the single-stage option
  • You’ll need to buy a replacement probe for saltwater setups

Best DIY Option: Ranco Temperature Controller

This temperature controller is a DIY option, meaning you’ll have to wire it yourself. It requires some technical knowledge, but it can be customized to suit your exact needs.

It comes in both single-stage and dual-stage options, so you’ll have your choice between just a heater and a heater/cooler option.

It’s durable and feels like it will last a long time, and it’s very accurate.

This controller doesn’t include an alarm, so you’ll have to go without one or purchase and integrate one yourself.

It’s a bit on the pricey side, especially for an option that requires additional parts.


  • It comes in single-stage and dual-stage options
  • It’s made with durable materials that will likely last for years


  • You can customize it to meet your exact needs
  • It’s highly accurate and reliable


  • It requires technical experience and knowledge to use correctly and safely
  • It doesn’t include an alarm
  • It’s a bit on the pricey side

Good Alternative: Finnex Temperature Controller

This temperature controller is less powerful than many other options, but it can still handle 800W heating elements.

This is a single-stage controller, so you won’t be able to run a chiller with it. However, it has upper and lower temperature settings to protect your water from spikes in both directions.

It includes an audible alarm to alert you to dangerous fluctuations, offering some peace of mind.

It’s more expensive than many other options. However, it is durable and reliable, so we still feel that it’s a good option for simple tank setups.


  • It includes an audible alarm to alert you to temperature spikes
  • It’s made of durable materials that will likely last through years of use


  • The temperature probe is very accurate and reliable
  • The included LCD screen displays useful temperature readings and settings


  • It’s more costly than other options
  • You can’t use this with a chiller, so you’ll be limited to heaters

Good Alternative: Bayite Pre-Wired Temperature Controller

This is a dual-stage controller that you can use with both a heater and a chiller. It allows for very precise control in both directions and maintains accurate temperatures, making it an excellent option for saltwater and freshwater tanks.

It’s a bit challenging to set up and adjust, and the LCD screens show you your minimum and maximum temperatures, as well as what action the controller is taking.

The temperature probe can corrode in saltwater, so you’ll need to replace it if you have a marine setup.

It’s very affordable, especially given the features it has.


  • Includes clear LCD readings of your set parameters
  • It includes a highly accurate temperature probe


  • You can use this with both heaters and chillers
  • It maintains very precise temperatures
  • It’s very affordable


  • The probe will need to be replaced for marine setups
  • It’s a bit challenging to set and adjust your desired temperatures

Aquarium Temperature Controller FAQs

How Do I Control the Temperature of My Fish Tank?

The safest and most accurate way to control your fish tank’s temperature is with an aquarium controller. These devices accurately monitor your tank water and cycle on heaters and chillers to maintain your desired water conditions.

Why Do Aquarium Heaters Fail?

All equipment fails over time, but aquarium heaters are particularly prone to malfunction. The biggest reason is that their temperature probes remain underwater, and the humidity makes them inaccurate. When the probe fails, your heater can remain on continuously, spiking the temperature to dangerous or deadly levels.

Can a Fish Tank Catch Fire?

Fish tank equipment can catch fire. If the pieces are poorly made or misused, your tank water can mix with electrical components and cause a fire. This is not only dangerous to your tank inhabitants, but it can lead to property damage, personal injury, and death.

How Long Does it Take an Aquarium Heater to Heat Water?

The exact time depends on your tank size and heater capacity. If you purchase a heater rated exactly for your tank volume, it can take around 24 hours to get up to the desired temperature. More powerful heaters can get the job done in about 6 hours.

Can Aquarium Heaters Kill Fish?

Unfortunately, aquarium heaters can kill your fish and other tank inhabitants. Heaters malfunction with some regularity, and if the heating element fails, your tank water can reach low temperatures that can kill your fish. If the temperature probe fails, the heater may remain on constantly and cook your fish.

What Temperature Should My Aquarium Heater Be Set At?

Different fish species require varying temperatures to survive and thrive, so your heater should be set for your specific fish. Many heaters aren’t entirely accurate, so you can either set a temperature and continuously adjust until the desired setting is reached, or you can use a far more accurate aquarium temperature controller to modulate the temperature.


Aquarium temperature controllers make dialing in and maintaining the perfect temperature in your tank a breeze. You can choose one that both heats and cools your water, has a high degree of accuracy, and includes an alarm that alerts you if your water temperature falls outside your parameters.

Our overall recommendation for a temperature controller is the Inkbird ITC-306T. It’s straightforward to set up and use, it’s reliable and accurate, and it has an alarm to help you identify heater failure and save your fish from dangerously high or low temperatures.

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