Chillers

Used primarily in reef aquariums, chillers are fan-cooled refrigeration units that use compressed air and heat exchange coils to lower the temperature of tank water. A pump is needed to deliver tank water to and from most models of chillers. There are also stand-alone "drop in chillers" that can be placed in the sump area of a tank filtration system to absorb heat. Chillers are used in some reef tanks, as well as in cold and temperate aquariums housing some goldfish species.