In an aquarium, a stable water temperature is an important factor in maintaining fish and invertebrate health.
While small temperature fluctuations are OK, dramatic swings can cause stress and lead to disease problems or eventual death to aquarium inhabitants.
Tropical freshwater aquariums are usually kept at 75-80°F. Reef tanks with corals are kept in a range of 75-77°F.
In many homes, modern HVAC systems automatically lower room temperature at night or when no one is home. This saves energy but can cause the aquarium water temperature to dip too low. An aquarium heater solves this problem.
In this article
Basics of Aquarium Heaters
You may be familiar with the basic aquarium heater. The heating element and temperature sensor are encased in a glass, stainless steel, or polymer tube.
Temperature modifications are made by turning the thermostat on top of the heater tube.You have to make a temperature adjustment, wait a few hours for the water temperature to stabilize, and make readjustment until the correct temperature is dialed-in.
This design has been around for over 50 years. While it has proven effective, a new type of temperature control system is available to freshwater and marine aquarists.
Stand-alone temperature controllers provide greater control and ease of use. Here’s how they work.
How Heater Controllers Work
Heater controllers bypass the need for a heater with temperature sensor and built-in thermostat.
Heater controllers are programmable sensing and control devices that switch a dedicated heating tube on and off based on aquarium water temperature.
The controller has its own temperature probe that is placed in the aquarium. It sends water temperature information to the controller, which turns the heater on and off based on the setting you dial into the controller.
The water temperature and thermostat settings are displayed on an LCD or LED display.
Single and Dual-Stage Heater Controllers
There are two types of heater controllers. A single-stage controller turns the heater on and off based on a single temperature setting.
If the water temperature drops past the setting, the heater is switched on until the sensor indicates the water is warm enough.
A dual-output controller allows you to run two devices on the same controller.You’ll be able to control a submersible heater when the water is cool and a small chiller or cooling fan if the water gets too warm.
This is helpful if your home gets warm in the summer, you’ve got a reef with SPS or LPS corals, or room temperatures swing from low to high.
Why Upgrade to a Heater Controller?
Heater controllers offer several benefits over traditional heaters. The controller is completely separate from the heater tube. You can place it under your aquarium or in a location for easy access.
The digital display makes for at-a-glance temperature monitoring. You don’t have to put your hands into the aquarium to adjust the temperature.
If you’ve got a reef tank with a sump, the probe can be placed in the aquarium and heater installed out of sight, down in the sump.
Top Heater Controllers for Aquarium
We’ve taken a look at several popular heater controllers. Some offer more features. Check them out below to see which one is right for your aquarium.
The Aqua Logic controller is a heavy-duty device designed for controlling a heater or chiller.
This unit provides power for heaters up to 1000 watts. It can also handle the amperage draw of chillers up to ½ HP.
The power cables use heavy-gauge wire to handle the high current draw. The water-tight enclosure protects against moisture and splashes.
Temperature is easily set with just a few touches on the front panel. The LCD display shows the current temperature.
The temperature settings are retained, even after a power failure. If you want to control a heater and chiller, a dual-stage controller is also available.
Aqua Logic controllers are perfect for high-humidity environments or where you are using large heaters or chillers.
Finnex designed this digital heater controller with home aquariums in mind. It can control a heating unit up to 800 watts.
The temperature probe comes with a 6-foot cord and a suction cup for easy mounting in the aquarium or sump.
The LED display shows the temperature and settings. Smaller LEDs indicate that the unit is powered and heating.
The temperature control range is 67-93F. The controller allows you to set high and low set-points. This prevents the heater from rapidly cycling on and off needlessly. This extends the heating unit’s life and makes for a more even water temperature in the aquarium.
There’s also an audible low-high alert to protect your fish and invertebrates. Finnex also offers heaters with the controller hard-wired to the heating unit.
The Finnex titanium heater units are ideal for reef aquariums but can also be used in freshwater tanks.
JBJ is best known for their line of reef aquarium chillers. This is a basic temperature controller designed for one submersible heater.
The controller mounts above the aquarium or in the cabinet. The red LED display is easy to read from a distance. The three-prong grounded outlet will handle up to 1000 watts.
Setting the temperature takes just a press of the buttons on the front control panel. A LED indicates when the unit is heating the aquarium. The JBJ TrueTemp controller allows you to calibrate the temperature probe with an accurate thermometer.
An integrated smart memory chip will restore the previous temperature setting once the power returns after a power failure. The temperature range is 32-95F.
The Inkbird controller is a dual-stage controller for regulating heating and cooling equipment used in hydroponics, brewing, and other temperature-sensitive activities.
The controller uses similar technology as aquarium heater controllers and can be used with freshwater and marine tanks. The LED display shows the water temperature and the controller setting at the same time.
The two outlets are rated for a total of 10 amps. Care must be taken not to overload the controller when operating chillers and heaters at the same time.
The temperature sensor can be user-calibrated. The temperature sensor accuracy is +/- 2F. The outlet power cord is 12-inches long.
Recommendations
The Aqua Logic heater controller is used mainly for controlling temperature control systems in commercial aquariums but is easy to use in any aquarium setting.
The unit is very simple but constructed with reliable, high-quality materials and electronics. This is recommended for high-wattage heaters or larger chillers that require a temperature controller.
If you’re looking for a sturdy, highly-reliable controller, the Aqua Logic is highly recommended.
The Finnex and Inkbird have similar features. Finnex offers matched heating units for their aquarium controllers.
The longer power cords and temperature probes are very aquarium-friendly.With Inkbird, you’ll need to select an aquarium heater to plug into the controller’s power outlet.
Inkbird has a good reputation among aquarists even though Inkbird is not an aquarium product manufacturer. The company responds quickly to warranty issues.
If you have any questions or comments, please leave them below.