How To Install A Heater In An Aquarium

Last week I was thinking about placing a heater in an aquarium. There are many controversial advice on the Internet and in books. I do not consider myself an authority in thermodynamics, but I would like to publish my thoughts on this topic, as well as what others say. If you think that you have a good idea of ​​where the heater should be placed, please share in the comments.

Heat distribution in the aquarium

There are three ways in which heat can be distributed throughout your aquarium. This is thermal conductivity, convection and circulation.

Thermal conductivity is the usual distribution of heat from hot to cold to maintain thermal equilibrium. When water is heated, the water molecules receive more kinetic energy and begin to move, and thermal energy spreads throughout the water. Water is a good conductor of heat, but we want more heat transfer effects from convection and circulation.

Convection is when the heated water becomes less dense and rises to the top, creating convection currents. When your heater heats the water, it rises to the top to replace the volume of cold water.

The main means of obtaining heat in your tank will be the circulation of water in the filter. Ideally, your filter will mix water thoroughly so that hot or cold zones are not created.

What others say

Many believe that the place for the heater is where there are many streams that distribute heat evenly. This is achieved where warm water from the heater will be sucked in by a filter from the bottom of the aquarium.

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In one famous book, Aquariums for Dummies, the author says that the heater should be placed diagonally from top to bottom. I do not understand why and how to explain it.

Also in the manuals for freshwater aquariums, it is proposed to put the heater horizontally, just above the gravel near the filter. It mixes the hot area near the heater with total aquarium water. It is also proposed to use two small heaters for large aquariums. This gives you two advantages, if one fails, the second continues to work, and also provides better heat distribution.


Indeed, it is better to have a fully immersion heater for the aquarium, as well as a partially immersion heater, because you have more freedom in choosing a place to place.
Some immersion heaters do not work for a long time if you install them horizontally, and it’s risky to have to buy a new one once a year.

How To Install A Heater In An Aquarium

As you can see in the figure, in my 60 liter aquarium, the immersion heater is placed horizontally near the filter. Do not laugh, work on registration to be in the process. This placement makes sense to me, since I will use convection and circulation to transfer heat.

How To Install A Heater In An Aquarium

If I had a larger aquarium, I would install two small heaters. One horizontal in the lower right corner and one horizontal in the lower left corner. And also considered the possibility of installing an air dispenser below each heater for better circulation.
In this case, as a spray, I think to use a porous stone or a long porous tube so that the air bubbles also perform the function of hiding the heater from the eyes.
How do you set out ideas are bad or good? I would be very grateful if you state your thoughts in the comments.