Keeping the correct temp in your fish tank will help decrease stress of your corals fish and plants.

JBJ offers a great selection of True Temp heaters for the winter to keep everything nice and warm.

For those high light applications or warm rooms you may look into the Arctica Aquarium Chillers.  These coolers remove the heat from the water to provide a set temperature.  Many commercial chillers are used in laboratories and fish rooms around the world.

If you are looking at just removing some of the heat the C-Breeze fan may be a lower cost option.

For monitoring the precise temp of the water check out the Digitemp and Digi Temp 2 thermometers.