Heating Aquarium Water with a Submersible Heater Do Know It Aquarium Tropical fish and plants require warmth to keep them alive. Outside their preferred range, their bodies cease to function properly and they ... 72 72

Heating Aquarium Water with a Submersible Heater

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Tropical fish and plants require warmth to keep them alive. Outside their preferred range, their bodies cease to function properly and they die. Heating the water is very important for tropical aquarium fish in cold countries.

Image of thermostat heater inside
Inside a thermostat heater

The temperature of the water also affects its oxygen-holding capacity; the warmer the water, the less oxygen it can hold, and species that are not accustomed to lower oxygen levels will be seen gasping at the surface.

In cooler conditions, the fish tend to slow down and rest near the bottom. Plants may put on a spurt of growth and become straggly or they may disintegrate. Fortunately, with modern technology, maintaining the water at a natural level of 23-24°C (73-75°F) is quite easy to accomplish using one of the heating units available from your local aquarium dealer.

Now, you may be thinking that in a centrally heated home you do not need a heater - not so! During the day, the ambient room temperature may keep the aquarium water just warm enough. However, it will not raise the water temperature to that of the room; the water will be several degrees lower than the room temperature, so what happens during the night when the heating is turned down to allow you to sleep in comfort? The tank temperature drops, perhaps to critical or even fatal levels. It is therefore up to you to provide the correct temperature range and a heater-thermostat will accomplish this.

Power outages

There may come a time when you have a power outage. Short outages are not a problem, as the tank will cool slowly and then warm slowly, causing the fish no great stress provided it does not cool too far. It is worth calling your utility company to get an idea of how long the lack of service will last. If it is protracted, wrap a blanket around and over the tank to slow down chilling.
If you have an alternative source of heating, fill plastic bottles with hot water and float them in the aquarium. In most cases, the reduction in the water temperature is not the main cause for concern.

Types of heaters

The combined submersible heater-thermostat is the ideal choice for the novice fishkeeper. It is easy to regulate and, being submersible, cannot easily tamper with once set at the desired temperature. Separate heaters are also available in the form of submersible heaters or undertank heating mats. Both are controlled by either external or internal thermostats. (Children love fiddling with the knobs on an external thermostat, so be careful where you place them!) There are also power filters on the market that incorporate a heating unit in the system.

Under: Combined heater-thermostats are easy to adjust by turning the knob at the top until you reach the desired temperature. Models are available calibrated in °C or °F or both scales side by side. Some units have a light to indicate whether it is on or off. Make sure you can see this.

Image of combined heater-thermostat
A combined heater-thermostat

How to install the heater?

Safety first

Never turn on the heater until the tank is full of water.
Unpack the heater-thermostat and keep the instructions that tell you how to position and adjust it. Read these carefully, as there may be variations between manufacturers. Attach the suction cups. Check to see what temperature it is set at and adjust if necessary.

Below: The suction cups are usually supplied detached from the unit. Place them over the heater and slide them along so that one is near the top and the other near the bottom. You may need to wet them to stick them to the glass. Always keep spare suction cups and a spare heater-thermostat in stock.
Image of A heater with detached suction cups
A heater with detached suction cups

Most manufacturers recommend placing the heater at an angle (heating element at the bottom), so that as the heat rises, it does not go straight past the thermostat.

Leave a small space between the bottom of the heater and the substrate. Do not cover units with substrate as they will overheat. Make sure the water ~ flow is not obstructed by any tank decorations placed in front of the heater.

As the water is circulated by the filter, it will pass the heater and warm up.

What is a good size for heater?

The size heater you need (wattage) will depend on the size of your aquarium. As a guide, you need 50 watts per 27 liters (6 gallons) of water.

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