Temperature

Temperature is an essential factor in the operation of a marine aquarium. Aquatic organisms normally occur at water temperatures from -2 to about 30°C. A few specialized bacteria and archaea (extremophiles) are comfortable in extreme heat up to 130°C.

The temperature has influence on many factors / parameters. Aquarium relevant parameters are:

• Solubility of gases: the higher the temperature the less gases can dissolve in the water.
• pH value
• Density: as the temperature increases (above 4°C) water expands.
• Electrical conductivity: the higher the temperature the lower the electrical conductivity (not to be confused with conductance).
• Solubility of salts: the higher the temperatures the better salts can be dissolved.
• Evaporation: the higher the temperature difference between water and air temperature, the faster the water evaporates.
• Chemical reactions: the higher the temperature, the faster chemical reactions take place.
• Electronic components: the higher the temperature, the more electronic components suffer, especially LEDs.
• Corrosion: the higher the temperature the more corrosion.

Possibility of heating aquariums:

• Heating mats (only for small aquariums)
• Rod heaters: are available from a few watts up to several kW.
• Heat exchanger: can be connected to the central heating system.
• About room temperature: most reef aquariums do not need additional heating. The heat input from room temperature, pumps and lighting is usually quite sufficient.

Options for cooling aquariums:

• Air passing over the water surface (fans).
• Cooling unit with heat exchanger
• Heat exchanger: can be connected to a central air conditioning system.
• Via room temperature: if air conditioning is installed in the room, a reef aquarium does not normally require additional cooling.
• A bag filled with ice cubes only has an effect in very small aquariums (nano aquariums).

Changing the temperature should always be done slowly.

Optimal temperatures:
tropical coral reef aquarium: around 20...27°C,
temperatures above 30°C should never be exceeded.