How To Use An Aquarium Heater

A typical aquarium heater

Not all aquariums need a heater in them, it all depends on what kind of fish you want to keep. Tropical freshwater setups and marine setups certainly will be needing one though. In general, a cold water tank shouldn’t need one but it really depends on what the room temperature is where the tank is placed. Say for instance you live in a cold part of the world and temperatures plummet at night you may well need to steady the temperature in your tank.

Aquarium heaters come in a few different shapes and sizes and it can be a bit daunting to a beginner setting them up. After all, you don’t want your tank too cold, and certainly don’t want it too hot either. In this article, I shall look at things such as where to place your aquarium heater, what temperature to have your aquarium heater set at and what size heater you should purchase.

What Type Of Aquarium Heaters Are There?

When choosing a heater for your aquarium you will more than likely come across 4 different types to choose from. The most common one you will see is the submersible one, these have been around for as long as I remember. Other types also include Substrate heaters, inline heaters, and hanging heaters.

Submersible Heaters

As the name suggests submersible heaters are designed to be totally submerged in the water. These are usually made of glass, and stuck to the side of a tank via suction cups. Being submersible has several advantages such as better distribution of the heat around your tank and are easy to hide from sight. There are plenty of brands to choose from but I have always found Fluval heaters to be pretty reliable. When purchasing your heater if you plan on having it near the bottom of your tank be sure to check it is indeed a submersible one.

Substrate Heaters

Substrate heaters are made up of wire cables or coils that are placed under your substrate. These cables are then heated, this causes heat to rise up through the water column and warm the water as it goes. These types of heaters are particularly beneficial if you have live plants in your tank. The heat rising in the tank causes a type of thermal and pushes nutrients evenly around the water. These types of heaters work better with substrates such as course soil, pea shingle, and gravel. The heat tends to escape through it a lot easier and can be evenly distributed.

Inline Heater

If you have an external filter set up with your tank, then an inline heater may be the one for you. An inline filter is attached to your filter hoses. Thus letting the water pass through the heating element while it is being circulated around your tank. This gives a good even distribution of heat. It also allows you to have one less thing in your tank to look at. Because it is externally fitted you are able to hide it in a cabinet or behind your tank.

Hanging Heaters

As you can probably tell by the name these heaters hang off the side of your tank. These are not designed to be fully submerged in the water. To me, these heaters are only suited for very small tanks. As most of us know heat rises and these do not tend to sit very low in the water. Therefore you will end up with a cold zone nearer the bottom of the tank. I am not a big fan of these really and do not own one myself.

What Size Heater For My Aquarium?

When purchasing a heater for your setup you will need to work out what size you will need. If the room temperature is around 70 degrees you will need roughly 5 watts of power to every gallon of water in your tank. This will work efficiently up to about 50 gallons in size. Any larger tanks you will need about 3 watts of power for every gallon. If the room that the tank is in is particularly cold, you may have to up the wattage or get yourself a second heater.

Where To Place A Submersible Aquarium Heater

One of the questions I always get asked is ‘where do I place my heater’? A lot of people new to the hobby of fish keeping may just plonk it in the tank and not think too much about it. Although the position of the heater isn’t exactly critical, there are a few things to take into consideration. By following these tips your heater will be used efficiently and to its maximum potential.

Most people when they first buy a heater place it in the tank vertically. This, in my eyes, isn’t the best position for it. Most standard heaters have the heating element at the end furthest from the cable, and the thermostat at the other end. So when it is positioned vertically the heat will rise straight up to the thermostat. This in turn will switch the thermostat off before the bottom of the tank has reached your desired temperature. I tend to lay my heater a few inches off the bottom in a horizontal position. This means that all the water in your tank warms up before the thermostat kicks in. Another good reason for the heater being low in the water is water changes. If the heater is down near the bottom you won’t have to mess around turning it off when changing your water.

Another thing worth noting is where the inlet for your filter is. If you can place the heater within the vicinity of your inlet the heat will circulate around your tank more efficiently. This will ensure the heat is distributed evenly around your setup.

The back wall of your tank or a sidewall is usually the preferred place to put a heater. Mainly because it is easier to obscure it with the help of plants or ornaments. Just be sure that nothing actually touches the heater itself though. This could lead to a damaged heater. Live plants could also suffer damage if the heater is powerful enough.

Useful Tips For An Aquarium Heater

  • Be sure to check your heater once in a while for cracks. If you do see a crack dispose of the heater instantly and purchase another one.
  • When placing a heater in your tank make sure you leave it for half an hour before you turn it on.
  • When purchasing a heater always buy a branded name. A faulty heater could be disasterous, it certainly pays to buy quality.
  • Bare in mind that heat rises. When placing your heater keep it near the bottom of the tank for better heat distribution.
  • Make sure no plants or ornaments are touching the heater, this could cause unnecessary damage to the components.

Frequently Asked Questions

What temperature should my heater be?

Most tropical fish like their temperature around 75 to 80F and fish such as goldfish like it colder around 68 to 74F. This is just a general rule and can vary between the species. So be sure to check that all the fish you buy like the same temperature to thrive.

Can my heater burn a fish?

The answer to this is yes it is possible but unlikely. The fish would have to be stuck against the heating element to sustain any type of burn. For this reason, be sure to check your fish cannot get stuck between your heater and the side of your tank.

Do I leave a fish tank heater on all the time?

Yes you should leave the fish tank heater on at all times. The heater has a built in thermostat that will switch it off when it gets to your desired temperature setting.

Do all fish need a heater?

Absolutely not, there is plenty of fish that do not need tropical conditions to live. But by having a heater your choice of fish and plants will be increased dramatically.

Are heaters expensive to run?

No, heaters are relatively to run nowadays. It obviously depends on the size of your heater but most of them just cost a few pence a day.

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