Aquarium Heater Size Guide

To determine which heater is required for your particular aquarium and environment follow the instructions below:

• Calculate the average temperature of the room that you are to locate the aquarium.
• Identify the desired water temperature for your fish.
• Subtract the average room temperature from the desired water temperature.
• This will give the amount of heating required.

Example

Average room temperature 69 degrees F
Desired water temperature 78 degrees F

Heating required                      9 degrees F

Using the the aquarium heater size guide below, find the size of your aquarium in the left hand column and move to the column that shows the number of degrees to which the aquarium is to be heated. If the heating requirement is between two levels, move to the next larger size.

For larger tanks, or where the room temperature is significantly below the desired water temperature, two heaters may be required. In this case the heaters should be installed at opposite ends of the tank so as to heat the aquarium evenly.


Tank Size           Heat 5 to 9 degrees F       Heat 10 to 18 Degrees F      Heat 15 to 27 Degrees F

  25 Litres                  25 Watts                               50 Watts                                      75 Watts     
  50 L                          50 Watts                               75 Watts                                      75 Watts 
  75 L                          50 Watts                               75 Watts                                     150 Watts
100 L                          75 Watts                             100 Watts                                    200 Watts
150 L                        100 Watts                             150 Watts                                    300 Watts
200 L                        150 Watts                             200 Watts                                    Two 200 Watts
250 L                        200 Watts                             250 Watts                                    Two 250 Watts
300 L                        250 Watts                             300 Watts                                    Two 300 Watts