Generally salt water aquariums are described using the term marine aquariums. Marine fish need a different environment to live in than tropical fish, and therefore you need different equipment.
The most obvious difference between marine and tropical aquariums is that you need salt. This does not mean you can use table salt, instead you need marine salt, which is made from either a desalination process of natural seawater or man made using the correct balance of elements and additives.
A vital piece of equipment that you need to keep salt water aquariums is a hydrometer, as this will tell you how much salt is in the water. You should use one when preparing water for water changes in your tank, and occasionally use it to check the main tank. They are very easy to use and not expensive to buy, and some even come with built in thermometers.
For a salt water aquarium you will also need a protein skimmer. This is piece of equipment is essential to help you keep clean marine water. A protein skimmer is basically a pre-filter that should be used alongside a conventional filter in your tank. They work by creating tiny bubbles that rise to the surface of the water through a plastic column, into a collection bowl above the surface.
As the bubbles rise they collect sticky proteins from the water, removing them along with other potential toxins, such as ammonia and nitrite. There are loads of different kinds of protein skimmers available, including internal and external models.
Get some advice from an expert when you choose one for your tank but buy the biggest one you can afford that will fit your tank, as it will be the most efficient. When choosing your tank make sure it can take a skimmer if you plan on keeping marine fish.
Other equipment you will need for your salt water aquarium includes a chiller or a cooler. As we use more and more equipment these days in our tanks more heat is being produced by the power. One of the major causes of heat is powerful lighting in our aquariums, so the way to combat this extra heat is to use a chiller or a cooler.
These are a kind of refrigeration unit that connects to the tank. Water gets pumped through this unit, where it is cooled, and then sent back to the tank. Some units are coolers and heaters so they can control the exact temperature.
There is lots of other equipment available for salt water aquariums that you may or may not need. To get a basic set for a marine tank do some thorough research and talk to an expert if necessary. If you are converting a tank make sure it can take all the equipment you need to successfully keep marines.