Saltwater Aquarium for Beginners

For many people interested in the fishkeeping hobby, creating a successful saltwater aquarium is the ultimate goal. A good saltwater aquarium can be stunning to look at, from the bright colors of the fish and coral to the tiny details of the mini-ecosystem on display. With so many different options, a saltwater aquarium can be truly unique and your own.

a saltwater reef tank

None of this comes simply, however. Saltwater aquariums involve more work, more time and more money than a typical freshwater aquarium. That’s why I’d usually recommend a beginner to stick with a freshwater system at first, at least until they’ve learnt all the ins and outs, and made sure fishkeeping is definitely a hobby that interests them. Of course, this is by no means necessary. Beginners can and often do succeed with saltwater aquariums, as long as they are willing to do the research and maintenance required to keep their system healthy.

If that describes you, then you’ll find this guide useful. It takes you through all the basics you need to know if you want to set up a saltwater aquarium for beginners. We’re going to cover what you need to know before you start, how to set up your saltwater aquarium and what you need to do to maintain a healthy tank. If you’ve kept a freshwater tank before, you might be familiar with some of this information, as this is written for beginners who have never owned any aquarium before. However, there will still be plenty of new information for you to take in.


The Equipment

The tank

multiple empty fish tanks

Which tank is right for you?

You might think that as a beginner, you should choose a small tank. Smaller should mean easier, right? Wrong. The best thing to do, especially as a beginner, is get the biggest tank you can afford for the space you have available. A bigger aquarium has more water, and more water means more stable parameters. Maintaining stable water parameters is one of the most important things you can do to keep your fish healthy and happy, and a larger tank means any disruptions will give you more time to fix them before they start causing major problems.

A larger aquarium will also give you the option of keeping bigger and more active fish, or a larger population of small fish.

While bigger is generally better, you should also think about the minimum size for your tank. This will depend on what fish you want to put in there, so make sure you research your preferred saltwater fish before buying anything. Mistakes here will end up wasting your time and your money, not to mention you could have a very unhappy fish on your hands.



Live rock

Live rock, used for biological filtration.

Filtration is one of the most important parts of any aquarium set up, but especially so for a saltwater aquarium. You need to filter your water to ensure that harmful waste doesn’t build up in your tank, such as from fish waste, uneaten food or ammonia directly from the gills of your fish.

There are a few different types of filtration you should be aware of, and we’re going to start with biological filtration.

Biological filtration takes advantage of naturally occurring bacteria, usually added to a tank with the use of live rock. The bacteria in this live rock, given enough time, will multiply to the point where they are able to deal with the ammonia produced in your aquarium. These bacteria will take the ammonia and change it into a less toxic compound, known as nitrite. Nitrite might not be as bad as ammonia, but it is still bad news for your fish. So the bacteria then change this nitrite into another compound, nitrate. Nitrate is much less toxic than both ammonia and nitrite.

Within your saltwater aquarium, you want your ammonia and nitrite levels to be 0 ppm. Nitrate, being less harmful, should ideally be lower than 30 ppm.

An important aspect of biological filtration if water flow. For the bacteria to effectively filter the ammonia and nitrites from your water, they need a constant flow of water through your filter media (probably live rock). The flow will not only ensure they have a constant supply of these chemicals, but also a constant supply of oxygen necessary for them to survive.

Those are the main points you need to know about biological filtration. Next is mechanical filtration.

Mechanical filtration takes care of the larger particles in your saltwater aquarium, such as bits of uneaten food and waste from your fish. This is much simpler to understand than biological filtration. A mechanical filter uses a sponge, filter wool or something similar to trap these solids and prevent them from returning into your aquarium. This makes your aquarium look nicer, but more importantly it reduces the toxic chemicals produced when fish waste or uneaten food decay.

For this filtration to be successful, you will need to wash or change the filter regularly. How often depends on the specifics of your aquarium.

Finally, there is chemical filtration. This type of filtration is used to eliminate small dissolved compounds from your saltwater aquarium water. The most common method of chemical filtration used in saltwater aquariums is a protein skimmer. Protein skimmers remove organic waste from your aquarium water before the bacteria has a chance to convert it, meaning less work for the bacteria.



Aquarium lighting is an important aspect of setting up an aquarium. Good lighting can be the difference between a beautiful looking saltwater aquarium, and a drab, unimpressive tank.

The specific type of lighting you need to get will depend on a few factors. Mainly, what are you keeping in your saltwater aquarium? If you have just fish and rock, lighting isn’t extremely important. Get something that you think looks good and you’ll be fine. For example, standard aquarium florescent lights will do just fine in this case.

If you’re setting up a saltwater reef tank, however, it’s a bit trickier. You coral is going to need light to photosynthesize, and different corals have different requirements when it comes to lighting. Not only that, but the size of your aquarium needs to be taken into account as well. Deeper tanks need stronger lights if you want sufficient light to reach the bottom. If you have coral placed close to the surface of the water in your tank, you can get away with weaker lights. Placing coral at the bottom of your tank on the other hand means that light has to penetrate further through the water, so much stronger lighting may be needed.



Tropical saltwater aquariums will generally need to be kept at a stable temperature between 75-79 °F. Going outside this range can put the health of your fish at risk. To maintain this temperature you’ll need to buy a heater for your aquarium. There is a wide variety of aquarium heaters available but it’s not too important which one you get. As long as it reliably heats your water, it should be fine. The main thing to note here is that you will need to get a heater powerful enough for your tank. Larger aquariums require more heating, so just check what size tank a heater is rated for before you buy it.

For the most effective heating of your aquarium, place your heater near an area of high flow. Near a filter intake would work well.

As I mentioned previously, a larger tank is beneficial here, as it will keep your temperature more stable and less vulnerable to rapid fluctuation.

Testing tools


aquarium water testing kit

An aquarium test kit

You’ll need a few tools to monitor the parameters of your aquarium, mainly ammonia, nitrite and nitrate levels, and salt content.

Salt content is best monitored using a refractometer, and should be kept as close as possible to 36 ppt. Avoid going more than 1 ppt in either direction.

Ammonia, nitrite and nitrates can be monitored using a simple testing kit. I mentioned ideal levels above, but will repeat them because of how important they are. Ammonia and nitrite levels should be at 0 ppm, nitrate levels below 30 ppm.

You can buy these tools online or at your local pet/aquarium store.


Other things you’ll need to buy for your saltwater aquarium include salt and aquarium substrate. For the substrate, there are many options out there and this is largely a personal choice. For the salt, make sure it is aquarium salt, not simple table salt.


So, that’s it for the essential equipment you’ll need for a basic saltwater aquarium for beginners. There is plenty more you can consider, including sumps, refugiums, and various reactors. However, for a basic beginner friendly set up, this should be enough equipment to get you started.


Setting Up Your Saltwater Aquarium


You’ve done your research. You’ve brought your supplies. Now it’s time to actually start bringing everything together and get your saltwater aquarium started.

First thing’s first, you’ll need to clean everything.

Wipe down your tank and equipment with warm water to get rid of any dust or debris. Don’t use cleaning chemicals, as these may leave residue and end up contaminating your aquarium.

Next, you need to clean your substrate by giving it a rinse. This just gets rid of any dust that would otherwise end up floating around in your water, making it cloudy.

With everything clean, it’s time to put your tank wherever you’ve decided you’re going to keep it. Hopefully you have a tank stand to place it on, or some other surface which you’re confident can handle the weight of a full aquarium.

Find suitable places for your filter and water heater, ideally near each other so there is high flow around the heater.

Now add your chosen substrate to the tank, followed by adding water. Do not use tap water for this, as it contains trace chemicals that will harm your fish. You need to use RO water, meaning water that has been filtered by a process called reverse osmosis. You can probably buy RO water from your local aquarium store, but in the long run it’s probably cheaper and less hassle to buy a RO filter yourself, so you have a supply of good water whenever you need it.

With your water added, put in the aquarium salt according to the instructions that came with the salt. Turn on your filter and heating to help the salt dissolve and disperse throughout the water.

Once it’s nicely dissolved, leave everything running for a few hours before measuring the pH, salinity and temperature of your water. When these levels are stable and you are happy with them, you can add your live rock to the aquarium.

After adding the live rock, there’s not much more you can do for the moment. You have to let your tank cycle, which allows the bacteria from the live rock to establish itself in your aquarium and ensures that your water parameters (i.e. ammonia, nitrite and nitrate levels) will remain stable once fish are added.

Cycling your aquarium will probably take between four and six weeks, during which time you should test your aquarium water frequently. Two or three times a week is more than enough. Hopefully you should be seeing ammonia and nitrite levels going down over time and eventually reaching zero. Nitrate levels on the other hand will be increasing, so you’ll need to do a few water changes throughout the cycle process to keep these levels down.

Important to note that when doing water changes, you can’t add pure water to your tank followed by an equivalent amount of salt. Your saltwater needs to be premixed before adding to your aquarium; otherwise, you may put your fish at risk.


Aquarium Maintenance


With your saltwater aquarium fully up and running by this point, you’re free to stock it with your fish of choice. Of course, I’d recommend doing a bit of research on any fish you’re interested in, making sure you understand their specific needs and how to keep them happy and healthy.

But that’s not the end of your work. To make sure your aquarium and its inhabitants stay healthy, you need to provide regular maintenance to keep everything running smoothly.

The first thing you need to be doing is regular tests on your water parameters. About once a week should be sufficient for salinity and ammonia, nitrite and nitrate levels, but you should keep a closer eye on your aquarium temperature. Make sure this is steady every day.

Next on the list is water changes.  How often you need to do this depends on how good your filtration is and how heavily your aquarium is stocked with fish, but a good rule of thumb is a 10 % water change every two weeks. This keeps nitrate levels in check. When adding water during a water change, the new water should match the parameters of your aquarium in term of salinity, pH and temperature.

The last bit of regular maintenance you’ll need to do is topping up your aquarium water level. Small amounts of water will be evaporating from your aquarium on a daily basis, but the salt from that water is left behind. This causes higher salinity in your aquarium, so you’ll need to top up with RO water (without salt) to bring your aquarium back to optimum levels.


So that’s all the basic information you need to set up a saltwater aquarium for beginners. This should be enough to get you up and running, but there is a lot more information out there on how to master the saltwater aquarium. Hopefully if this really is a hobby that interests you, you’ll enjoy learning all about it and setting up the best aquarium you can.

It might be a lot of work, but keeping a beautiful saltwater aquarium is one of the most rewarding things you can do in this hobby, and is something I wish more people would try their hand at.

Do you have any experience with saltwater aquariums? Let us know about it in the comments.

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