All You Need to Know of Aquarium Heaters

By | October 2, 2011

Aquarium heaters are probably some of the overlooked features of an aquarium, yet this is also one of the fundamental pieces of equipment on the reef tank.

Aquarium heaters are probably some of the overlooked features of an aquarium, yet this is also one of the fundamental pieces of equipment on the reef tank.

An aquarium can last for several days without lights or pumps but without the aquarium heaters, aquarium chillers and protein skimmers, a reef tank would not last a couple of hours.

Aquarium heaters come in two basic types, that is, those containing electronic thermostats and those with mechanical thermostats. Most heaters fall under the mechanical kind; however, some newer models are electronic.

Both mechanical and electronic aquarium heaters have similar basic parts with exception of what regulates the temperature and/or energizes the heating element.

Both types share common parts as the envelope, heating element and temperature adjustment knob. The envelope, made of either glass or titanium, keeps the internal components of the aquarium heaters and aquarium chillers dry. The heating element is simply a piece of resistance wire that is energized with 120V of electricity.

The mechanical heater has what is referred to as a bi-metal thermostat. It consists of two dissimilar metals bonded together. These expand and contract at different rates when heated or cooled, causing the strip to curve as the temperature changes. There is an electrical contact at one end of the metal strip. The adjustment knob either varies the distance between the contacts or varies the tension on the strip.

This adjustment distance is what permits the heater to be set for a specific temperature to create an electrical connection between the contacts. Electronic aquarium heaters have an electrical sensor inside. As the aquarium heaters and aquarium chillers temperature rises or falls, the output voltage of the sensor varies. This voltage signal controls an electronic switch that has no moving parts which turns the heating element on and off. The mechanical thermostats suffer problems that arise from their design. The bi metal strips are very small and quite delicate. Constant bending cause rapid metal fatigue, therefore it is very prone to breaking. The truth is that mechanical aquarium heaters and aquarium chillers fail with alarming regularity. The electrical one has its own problems and equally malfunctions as the mechanical one.

To solve this problem, many aquarium heaters, aquarium chillers manufacturers use multiple small heaters, which add a layer of redundancy and safety to the aquarium’s life support system. A dedicated temperature controller should be used to control the aquarium’s temperature. The controllers are designed to operate reliably and have a very low failure rate. Many hobby heaters come with controllers that mimic the look and functionality of the commercial unit. The best way of utilizing a controller is to set the thermostats on the individual heaters a few degrees above the controller’s set point. The controller will turn the heater on and off as demand requires. The aquarium heaters’ and aquarium chillers internal thermostats prevent the heater from running in the rare event that the dedicated temperature controller malfunctions. Here lies the fail-safe! The internal thermostats can not be prone to metal fatigue or arc damage because they are not used during normal operations.

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