The following is a general calculation method to choose the aquarium chillers (heat factor of the lights and pump ignored before). Please note earlier, to cool water 1°C increments of 1 liter in 1 hour needed 4 Btu (British thermal units).For example, 1000 liters aquarium - initially water temperature is 30 ° C, and the desired temperature is 25 ° C. So it takes 1000 liters x 4 Btu x (30 - 25 ° C) = 20,000 Btu.
If we use ½ HP chiller capacity (about 5000 Btu), the water chillers will run for 20.000/5.000 Btu = 4 hours. Furthermore, after the temperature reaches 25 ° C, the chiller will stop (not working) and start again at a temperature of 26 ° C (+1 ° C). After that, the time needed to lower the temperature into 25 ° C return is 1 hour.
If we use an aquarium chiller with a larger capacity, eg, 1 HP (about 9,000 Btu), then the time needed of the 1 HP chillers to work is a half of the working hours of ½ HP chillers
Conversely, if we use water chillers for aquarium with capacity less than ½ HP, then the time required for chiller to work become longer. This is what causes the chiller rapidly damaged due to lack of resources or working continuously without stopping.
Chillers capacity calculation is very important thing because a stable temperature is essential for the aquarium life community. It will make the inhabitants of the aquarium to avoid stress. Includes an aquarium plant, such as Visicularia dubyana which need temperatures about 20-25°C to grow well. The temperature can be obtained if the aquarium is equipped with the proper water chillers.