If you are considering to set up a fish tank to enjoy either at home or at your office, you can expect it to be more involved than filling a tank with water and tossing in some fish. There will be some special equipment required if you want to properly care for the fish for a long period of time. Most set-ups will need something called an aquarium chiller which serves to keep the water in the tank at a consistent temperature. During the heat of the summer months, aquarium chillers are especially needed to control the water temperature and help prevent the spread of disease and algae growth. You will most definitely need one if you will be running a marine tank that will contain cold water fish.

The system works basically like an air conditioner or refrigerator and utilizes the identical principles of gas expansion and contraction. A thermostat control unit can be set to the appropriate temperature and when the water temperature rises above the desired setting, the cooling unit turns on. By compressing the refrigeration gas, it becomes cooler and the cool gas is directed to a heat exchanger where it absorbs heat from the tank water, which has been pumped through the exchanger. Then, surplus heat gets carried by the gas back to the compressor and across an expansion valve. The valve causes a sudden pressure drop which results in the heat being transferred to the radiator, which releases the heat into the outside air by way of a fan. Finally, the cooled water is returned to the tank and the entire cycle repeats until the tank water is at the specified temperature.

There are a few different types of water cooling systems. Thermoelectric styles are quiet, energy-efficient, and should really only be used with smaller freshwater and saltwater tanks with a slow water flow. They are not effective on large tanks with a fast water flow. Drop-in types are available in a variety of sizes and horsepower. No plumbing is required so it makes the drop-in models perfect for tanks that have limited space. In-line models are used for larger systems that have in-line filtration because the water must be filtered before it is cooled. In-line styles require plumbing and are available in several sizes, so they will work with several sizes of tank sizes and are used mostly with saltwater setups.

When choosing a cooling system, one must consider the size of the tank, the additional equipment, and the temperature requirements of the fish. Marine tanks in particular usually require set ups, such as lighting and water pumps, which generate heat that raises the water temperature. Without a system to lower the water temperature, the water can warm up too much where it is unable to hold enough oxygen to sustain the fish. The cooling systems themselves produce a considerable amount of heat, so be sure to plan for sufficient space and adequate ventilation to avoid adding heat to the tank water.