Fan Speed Controller

The Fan Speed Controller is a small inline dial regulator that connects between the power supply and one or two aquarium cooling fans. By reducing voltage to the fan motors, it allows the keeper to dial down airflow from full speed to a gentle minimum, enabling fine-tuning of the evaporative cooling rate without switching fans on or off entirely.

Running fans at reduced speed has the dual benefit of generating less noise and reducing the rate of water evaporation — important in reef aquariums where topping off is labour-intensive and salinity fluctuations must be minimised. The controller is suitable for DC fan units typically used in aquarium cooling applications.

An inexpensive but practical accessory that turns a basic on/off fan into a variable-output cooling tool, particularly useful during transitional seasons when full cooling is not always required.