Aquarium Heater Guide

Aquarium Heater Guide

Aquariums house cold-blooded animals that depend on water temperature to maintain their body temperature. This means that the tank must be heated and maintained at a temperature suitable for the fish.

There are several types of heaters, one or more of which can be used depending on the installation location. The power or heating capacity of a heater is indicated by its wattage.


Types of Aquarium Heaters

You can choose what type of aquarium heater you want and how many you want to use.

Hang-on-tank: Suspended tank heaters are usually attached to the back of the aquarium with suction cups and/or hooks or other attachments around the edge of the aquarium. They are generally less efficient than other types of heaters because they are only partially submerged, but provide adequate heating in smaller aquariums. For use in larger aquariums, it is recommended that several heaters be hung on opposite sides of the tank.

Submersible: Submersible heaters are submerged in the water and are installed horizontally or vertically at the back of the tank. They are often installed horizontally near the substrate. Submersible heaters provide more stable and efficient heating than suspended heaters, especially in large aquariums.

Heating cable: A heating cable is installed under the gravel and connected to the control unit. This is useful in freshwater aquariums to avoid blind spots. However, this type of heater is not ideal for reef systems with saltwater fish, as the substrate must be dug up if the cable needs to be repaired or replaced.


Finding the Right Size of an Aquarium Heater

Aquarium Heater Size Chart

The size of an aquarium heater is based on the volume of water in the aquarium, the average temperature of the room where the aquarium is located, and the desired water temperature in the aquarium.

Some intelligent heaters can regulate the temperature, its power from 50W to 1000W are available, common is 100W, 200W, 300W, and 500W. This kind of heater can set the temperature in advance, and wait until the water temperature reaches the preset temperature. 

The heater will automatically shut down, if the water temperature is down, the heater will automatically turn on heating until the water temperature reaches the standard.

Generally speaking, a liter of water requires a power of 1.5W-2W heater. For example, if the aquarium has a length of 1 meter, a width of 0.5 meters, and a height of 0.6 meters, then its water capacity is about 300 liters, that is, the power needs to be a 500W-600W heater.

However, if the aquarium with a lid, you can use a smaller power heater, such as 300W, you can cover the aquarium lid, and test the temperature to see how much power is appropriate. In addition, based on experience, do not directly buy a 500W heater, but buy two 300W heaters.

Experienced aquarium users know that two 300W heaters should be placed at both ends of the aquarium so that the heat is evenly distributed and the effect is better. Another great advantage is that the two heaters will not be damaged at the same time. 

If one is damaged and not heated, the other one can continue to maintain the temperature will not be reduced too much or not reduced. The disadvantage of doing so is that the cost is slightly higher because if you buy two heaters, a 500W heater and a 300W price are almost the same.

A good rule of thumb for heater power is 2.5 to 5 watts per gallon of actual water volume in the aquarium. However, higher wattages are often required depending on the desired temperature. If multiple heaters are used, the combined heat output of all heaters must meet the required wattage.

To set the room temperature, the average room temperature is subtracted from the target temperature of the aquarium water. The result is the required heater wattage in degrees.

Using the aquarium heater sizing chart below, check the size of the aquarium in the left column and move to the column that indicates how many degrees the aquarium needs to be heated. If the required heat output is between two levels, select the next larger size. 

If your aquarium is small, it is not recommended to configure a high-power heater. Because if the performance of the heater is not good, it will be dangerous, especially when the heater is not in normal "work", the water temperature will rise rapidly, even boiling to cause fish death. Moreover, high temperatures will make the glass tank burst possible. Also, the smaller the aquarium, the faster the temperature rises.

The heater with too much power will start or stop frequently, which will easily damage the temperature control element and lead to heater failure. If it is a big aquarium, you can equip multiple small power heaters, the final heating effect is also the same.


Tips for the Use of Aquarium Heaters

In large aquariums or when the room temperature is well below the desired water temperature, two heaters can be used. The heaters should be placed at both ends of the aquarium to ensure even heating.

It is best to use multiple heaters, one hang-on heater, and one underwater heater. This will provide more even heat distribution and less stress on the heaters. Also, if one heater fails, the temperature cannot drop to a less dangerous level until a new heater is available. It is also advisable to purchase multiple heaters as replacements.

The length of the heater pipe is important as heat rises. As a general rule, the heater pipe should match the height of the aquarium.

Make sure there are no heat sources or room temperature fluctuations around the aquarium. The temperature may rise or fall if the aquarium is under a vent or near an intermittent heat source.

Always unplug the heater when draining the tank to avoid overheating when the tank is not submerged.

Some heaters have specific numeric settings for thermostat control that allow you to set the desired temperature. Some heaters control from low to high temperatures without displaying a specific temperature. The former is easier to use, but always check that the heater settings keep the aquarium at the correct temperature.

Heaters should be placed near the filter outlet to move the water and distribute the warm water throughout the aquarium.

Use an aquarium thermometer to check that the heater is keeping the water in the aquarium at the correct temperature. Check the temperature by moving the thermometer around several places in the aquarium to make sure the water temperature is even.

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