Chillers & Fans
Aquariums can easily over heat, both through hot weather and heat from light tubes or metal halide lights. Aquarium chillers are used to cool the water when the temperature goes too high and then maintain a set temperature. If the light source is then removed (lights switched off) and the temperature drops further, the chiller will switch off and not cool the water any further, leaving the aquariums heating system to maintain the temperature. Many marine aquarists use chillers (Aquarium fans) as a back up - too much heat and the corals will droop and then die - the chiller stops this happening.