Setting Up a Saltwater Aquarium

saltwater aquarium

There is nothing quite as beautiful as a saltwater aquarium full of healthy, colorful fish. A lot of people are reluctant to set up a saltwater aquarium because they feel it is too challenging. While it is true that it is easier if you are an experienced aquarist, you can set up a saltwater tank even if you are a beginner.

Here is what you'll need to get started:

The Aquarium

You will need to get the largest tank that you can afford and have room for. Larger aquariums have a greater water surface area for oxygen and carbon dioxide exchange than smaller tanks. In addition, because larger tanks have a larger volume of water, waste products from the fish will be more widely dispersed in a larger body of water. Larger tanks are also less likely to have wide temperature fluctuations.

The smallest size tank that you should attempt to keep saltwater fish in is 30 gallons, with an even larger tank (40 gallons or larger) being even better.

The shape of the tank is also important. Rectangular shapes are best because they provide the largest surface area. The worst kind of aquarium to buy are those that are taller than they are wide because the surface area at the top of the aquarium is too small for the volume of water. In addition, aquariums that are taller than they are wide don't allow much swimming room for the fish. Fish prefer to swim horizontally and not up and down.

For general guidelines about tank placement and other materials common to both fresh and marine aquarium setup please see the article Setting Up Your First Aquarium. The rest of this article will discuss only those aspects of marine aquariums that are unique to setting up a saltwater tank.


Unless you are setting up a reef aquarium, no special lighting is needed for marine fish. Providing you are not planning on setting up a reef tank, then a standard hood with a fluorescent lamp should be sufficient for your saltwater aquarium. If you are planning on setting up a reef tank then you will need special high output fluorescent lights or a metal halide lamp.


As with any fish tank you will need a good quality filter that is of the appropriate size and power for you tank. For the marine aquarium you will also need a protein skimmer.

What is a Protein Skimmer?

A protein skimmer removes waste products and organic compounds from your aquarium (in addition to your regular filtration system). The molecules of these waste products have a bipolar charge. The protein skimmer is a water filled chamber that produces small bubbles. The bubbles rise through the chamber, and because of their charge, the bipolar waste products are attracted to the bubbles. The bubbles/waste products then rise to the top of the chamber and produce a brown foam. The foam spills over into a collection cup on the skimmer and you simply discard the waste as needed.

Live Rock

Live rock serves as a biological filter. This is because live rock is colonized by beneficial bacteria that will feed on waste produced by the fish. These bacteria break down the waste products into compounds that aren't harmful to the fish. And no, the rock itself isn't alive, but it is full of microorganisms that are. These microrganisms provide an organic natural cleaning process to your tank, which is extremely beneficial to the well being of your fish. It also makes the cleaning process easier for you and will help to save you time, proper care and handling of the rock before installation is essential to keeping a clean tank.

You can buy uncured rock or cured rock. Cured rock is free of dead or dying organic matter, whereas uncured rock may have dead or dying reef organisms attached to it. If you buy uncured rock you will need to clean it yourself. Don't place uncured live rock into an aquarium that has fish or other life forms living in it. It is likely to have dead sponges, crustaceans, and other dying organisms that will seriously pollute the water. Cured rock is more expensive, but it is worth the added expense.

If you buy uncured rock you will have to cure it yourself. You do this by cleaning off all of the visible debris (keep it moist during this time) and then you place the uncured live rock into a saltwater filled container (not your aquarium). You must perform frequent water changes on this container for a week or two or until the water no longer smells bad. If there are still dying organisms on the rock then it is likely to have a foul odor.


As with any aquarium (saltwater or freshwater) you will need an aquarium heater and a thermometer. In general, the water temperature should be kept at about 74-78 degrees Fahrenheit or 23-26 degrees Celsius.


You'll need some sort of substrate to cover the bottom of your aquarium. Don't use the gravel commonly used for freshwater tanks. Instead, use crushed coral or sand (not sandbox sand). Your aquarium retailer should be able to help you with the choice of substrate.

Synthetic Salt Mix

You can buy packets of synthetic salt mix that approximate the conditions of seawater. Remember that you sometimes get what you pay for. Sometimes the cheapest salt mixes aren't the best for you fish. Also, keep in mind that you'll need to do frequent water changes and so you'll need enough salt to accommodate these.


For the marine aquarium you will need a hydrometer to measure the specific gravity of the water. This allows you to determine the salinity of the water.

Chlorine/Chloramine Removers and Reverse Osmosis Purifiers

Because tap water has been treated with either chlorine or chloramine to make it safe for human consumption you will need to use a chlorine/chloramine remover to make the water safe for your fish. Because tap water contains all kinds of heavy metals (e.g., copper, lead, ect.) it is also beneficial to use a reverse osmosis water purifier.

Ground Fault Circuit Interrupter

The combination of water and electicity are dangerous. Saltwater is an even greater conductor of electricity than freshwater is. A ground fault circuit interrupter will disrupt the flow of electricity in the event of accidental immersion (e.g., heater breaks, lighted hood dropped into tank).

Cycle the Aquarium

Once you have everything set up with the water and filtration running, live rock in place ect., then leave your aquarium running, but empty of fish until it cycles. You need to let your tank have enough time to acquire the proper levels of nitrifying bacteria that break down fish waste before adding the fish. You can jumpstart this process in two ways. You can buy some of this bacteria to add to the water or you can add a very small amount of fish food to the water each day for a couple of weeks. The bacteria will feed off the waste produced by the uneaten fish food and will allow your tank to cycle before you add the fish. If you add the fish before your tank cycles they will not survive.

And finally, you should purchase a good water test kit that allows you to measure the pH, ammonia, nitrite, and nitrate levels of the water.