How to Set up a Saltwater Aquarium: A Comprehensive Guide for Beginners


A saltwater aquarium is a fantastic way to bring the beauty of marine life into your living space. In this article, we’ll walk you through everything you need to know about how to set up a saltwater aquarium, including the aquarium itself, equipment, saltwater, fish, corals, and maintenance.

We will provide additional links to articles and blog posts that are a deeper dive into the information so you can learn at your own pace.

How to Set up a Saltwater Aquarium

How to set up a saltwater aquarium has a short list of steps to start – but a lifetime to master!

  • Buy an Aquarium: Select the best size aquarium and the best location for success.
  • Buy Equipment: Get at least the minimum viable necessary to keep the fish, invertebrates, and other livestock you anticipate.
  • Add Sand and Rock: Sand and rock are attractive and the foundation for biological filtration.
  • Add Saltwater: Buy premixed saltwater or (preferred) mix your own and start your nitrogen cycle.
  • Choose your Fish: Select your fish and other livestock. Take time to plan your livestock, as it is difficult to bounce back from a bad start.
  • Add Corals: Take your saltwater tank (optional) to a new level by making it a reef tank!
  • Routine Maintenance: You are responsible for the habitat and its success—plan on performing routine maintenance, to some degree, daily.

How to Set up a Saltwater Aquarium: The Aquarium

Choosing the right size saltwater aquarium

The first step is to choose the location of your aquarium. Choose a spot in your home that can support the tank’s weight when filled with water and that’s away from direct sunlight, heating vents, and air conditioners.

Direct sunlight can cause excessive algae growth, while temperature fluctuations can stress your marine life.

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The second step in starting your saltwater aquarium is choosing the correct size. Aquariums range from small nano tanks (less than 30 gallons) to large, room-dominating tanks (hundreds of gallons). Your choice will depend on your available space, budget, and the kind of marine life you want to keep.

Starting with a tank of at least 30-50 gallons is recommended for beginners. Larger tanks are more forgiving regarding water chemistry fluctuations and offer a more stable environment for your fish and corals. Additionally, a larger tank allows for a more diverse range of marine life.

Related Article: Best Low Iron Rimless Nano Aquariums

The best tank setups, in order of performance level, are as follows:

  • Best Performance: Display tank with a separate sump tank. A separate sump will house filters, pumps, protein skimmers, and probes away from view. It also adds water volume, making the tank easier to maintain.
  • Moderate Performance: All-In-One tanks (AIO) are display tanks manufactured with the sump or filtration compartments in the back. The AIO are not nearly as effective as display tanks with separate sumps because they provide no additional water volume and are too small to house properly sized equipment in many cases. They are a compromise you may have to make – as I have on many occasions.
  • Adequate Performance: Glass box. A display tank with no sump will require most equipment to hang on the back of the display tank and be visible. You lose a lot of flexibility, and your tank’s appearance suffers. Additionally, you also lose out on the increase in water volume.

How to Set up a Saltwater Aquarium: The Equipment

Filtration

Filtration is crucial for maintaining a healthy saltwater aquarium. The three types of filtration: are mechanical, chemical, and biological.

Mechanical filtration removes debris and detritus, chemical filtration removes dissolved waste and pollutants, and biological filtration breaks down ammonia and nitrite into less harmful substances for your livestock.

Many mechanical filters are available, such as canister, hang-on-back (HOB), and sump filters. Research the best option for your specific tank size and needs.

Biological filtration is discussed later, beginning in Sand and Rocks and then Cycling the Aquarium.

Heating and Cooling Equipment for Saltwater Tanks

A stable temperature is essential for the health of your livestock. Most saltwater fish and corals thrive at temperatures between 75-80°F. A heater is necessary to maintain this temperature, especially during colder months. An aquarium thermometer will help you monitor the temperature accurately.

Occasionally, an aquarium chiller may be needed to keep the temperature from getting too high, especially in warmer climates or if your aquarium receives direct sunlight.

Lighting Options For Your Aquarium

Proper lighting is vital for a saltwater aquarium, especially if you plan on keeping corals. Various lighting options are available, including LED, T5 fluorescent, and metal halide. LED lights provide a wide array of PAR and spectrum settings, are energy-efficient, have a long lifespan, and generate less heat than other options.

Related Article: Best Reef Lighting

Protein Skimmer Equipment

A protein skimmer is an essential piece of equipment for maintaining good water quality in a saltwater aquarium. It removes organic waste, which can lead to harmful substances like ammonia and nitrites. There are various protein skimmers, such as HOB and in-sump skimmers. Choose one that’s appropriate for your tank size.

Test Kits and Additional Aquarium Equipment

Invest in test kits to monitor water parameters such as salinity, pH, ammonia, nitrite, and nitrate. You’ll also need a refractometer or hydrometer to measure the salinity of your water.

You may also need a powerhead or wavemaker for water movement, an auto top-off system to maintain water levels, and a quarantine tank for new fish and corals.

How to Set up a Saltwater Aquarium: Sand and Rocks

Sand and rock not only help a reef tank look attractive, but they also serve as the most important filter in the tank. Beneficial bacteria populate the rock and sand to break down uneaten food and fish waste. These bacteria are your biological filter!

Sand: Sand is the easiest part of this equation. I recommend live sand from CaribSea to start your new biological filter. Live sand contains a broad spectrum of marine bacteria and compresses new tank cycling time. The sand’s surface area is great for housing beneficial bacteria.

Check out our article on seeding dry rock with live rock

Rock: There are many rock choices for your reef tank; it comes down to what you can afford. A few types of reef rock are:

  • Pre-cured live rock from a fish store. The fastest path and the most expensive at $8.00 – $10.00 per pound. It is also likely that some pests in this rock you might not want in your aquarium down the road. This rock is the pretty pink coralline algae that reefers love with an established bacteria load that will shorten the tank’s nitrogen cycling.
  • Real reef rock. This rock has been cured in saltwater and is shipped damp. It has purple coralline color and is pest free. The price is about $6.00 per pound.
  • Dry rock. Less expensive at around $3.00 per pound, this rock is white without any established bacteria. It also is pest-free and free of nuisance algae. A downside is that it will take months for the rock to change from white to purple. You can purchase dry rock in 10 to 25-pound boxes.

You can seed dry rock using live rock as a compromise between spending a fortune on live rock or saving money with dry rock that does little initially for your biological filter.

Reef Saver Dry Rock – 25 lb. and 45 lb. boxes with Free Shipping

How to Set up a Saltwater Aquarium: Saltwater

Mixing Saltwater for Your Tank

Creating artificial seawater for your saltwater aquarium by mixing marine salt with dechlorinated tap or purified water (e.g., reverse osmosis water). You’ll want to achieve a salinity level of around 1.023 to 1.025 specific gravity, which measures the salt concentration in the water.

Make sure to follow the manufacturer’s instructions on the marine salt package. Check your salinity with a refractometer.

Refractometers are available in various price ranges at your local fish store and online. Typically even the cheapest refractometer works 100 times better than a hydrometer. Amazon.com has a couple of models for under $40.

Cycling the Saltwater Aquarium

Before adding any marine life to your aquarium, you must cycle it. Cycling establishes beneficial bacteria in your tank, converting toxic ammonia and nitrite produced by fish waste into less harmful nitrate. This process usually takes 4-6 weeks.

To start cycling, you can add a source of ammonia, such as a piece of raw shrimp or fish food, and monitor ammonia, nitrite, and nitrate levels using test kits. Once ammonia and nitrite levels reach zero and nitrate levels are present, your tank is considered cycled and ready for livestock.

Another alternative to starting the nitrogen cycle is to start with a fish instead of raw shrimp or fish food. Some find this cruel because the fish is in the water before it is cycled.

Once you add your fish, it will immediately produce ammonia by breathing. Ammonia is also caused by decaying fish wastes and decaying fish food. Ammonia in the water is food for Nitrosomonas nitrifying bacteria. The bacteria will take the ammonia in and output Nitrite.

If you cycle with a live fish, add nitrifying bacteria and test your water regularly to ensure you aren’t subjecting your pet to harmful ammonia levels.

Important: Do not turn on your lights. Resist the urge to light your tank early. You will not want to light your tank until after the nitrogen cycle is complete – unless you love algae!

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How to Set up a Saltwater Aquarium: Fish

Choosing Your Saltwater Fish

When selecting fish for your saltwater aquarium, consider their compatibility, size, and behavior. It’s often suggested that beginners choose peaceful fish with similar environmental requirements that will not outgrow their tank.

Related Article: Best Saltwater Fish for Beginners

Research each species before purchasing to ensure a harmonious tank community.

Remember that you only get to add one fish to your aquarium initially. You want to stabilize the bacteria population for the amount of ammonia your first fish creates before adding another fish.

I have started all my saltwater reef tanks with live fish. I also use live rock and live sand at the start to stabilize the ammonia levels.

Fish-Safe Acclimation and Quarantine

When you bring home new fish, it’s crucial to acclimate them to your tank’s water parameters slowly to avoid stress.

Float the sealed bag containing your fish in your aquarium for 15-20 minutes to equalize the temperature. Then, gradually mix your aquarium water into the bag for 30-45 minutes to acclimate your fish to your tank’s specific water chemistry.

A quarantine tank is highly recommended to prevent the introduction of diseases or parasites into your main display tank.

Quarantine new fish for at least 2-4 weeks, observing them closely for any signs of illness before adding them to your main tank.

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How to Set up a Saltwater Aquarium: Corals

Types of Corals for Saltwater Reef Tanks

There are two main types of corals, soft and hard (stony.)

Beginner Corals: Soft corals are generally easier to care for and are more suitable for beginners. They include species like zoanthids, mushrooms, and leather corals.

Hard corals are divided into large polyp stony (LPS) and small polyp stony (SPS) corals. Hard corals are typically recommended to intermediate and advanced aquarists.

Related Article: 9 Best SPS Coral for Beginners

Intermediate Corals: LPS corals, such as Acanthastrea, and the Euphyllia family of the torch, hammer, and frogspawn corals, are generally more forgiving and suitable for intermediate aquarists.

How to Set up a Saltwater Aquarium
A mixture of soft and hard corals in a mixed reef tank

Advanced Corals: SPS corals, like Acropora and Montipora, can be more challenging to keep and are recommended for experienced hobbyists.

Coral Placement for Reef Tanks

How to Set up a Saltwater Aquarium for Corals: When placing corals in your aquarium, consider their lighting, water flow, and spacing requirements.

Some corals prefer low light and flow, while others require high light and strong water movement.

Leave enough space between corals to account for growth and to prevent them from stinging or shading each other.

Check out this beginner coral guide from Reef.com for placement advice!

How to Set up a Saltwater Aquarium: Maintenance

Aquarium Water Changes

Regular water changes are essential for maintaining a healthy saltwater aquarium. Water changes help remove waste, replenish essential minerals, and maintain stable water parameters. Changing 10-20% of the water every 1-2 weeks is recommended.

Water Parameter Testing for Saltwater Tanks

Monitor your water parameters regularly, including salinity, pH, ammonia, nitrite, nitrate, calcium, alkalinity, and magnesium. Keeping these parameters stable is essential for the health of your fish and corals.

Aquarium Cleaning and Equipment Maintenance

Regularly clean your aquarium glass, filter, and protein skimmer for optimal performance. Replace filter media as needed and clean your protein skimmer collection cup at least once weekly.

Check your equipment frequently to ensure everything works properly, and perform routine maintenance as the manufacturer recommends.

Algae Control in a Saltwater Tank

Algae growth is a common issue in saltwater aquariums. To control algae, maintain proper water parameters, limit excess nutrients, and avoid overfeeding your fish.

Regular water changes and using a protein skimmer will also help reduce algae growth. Introduce algae-eating fish and invertebrates, such as snails and hermit crabs, to help keep algae in check.

Check out our article on the Best Clean Up Crew for algae-eating fish and invertebrates.

Feeding Your Saltwater Livestock

Depending on their specific dietary requirements, feed your fish and corals a varied diet, including pellets, flakes, frozen foods, and live foods. Some corals can be target-fed with coral foods or small pieces of seafood, while others receive their nutrients from the lighting and dissolved nutrients in the water. Feed your fish small amounts of food 1-2 times daily, and remove any uneaten food to prevent water pollution.

Want to go deeper into How to Set Up a Saltwater Aquarium? Read Beginner Easy Quick Start Reef Tank Guide

Wrap-Up and Key Takeaways

Starting a saltwater aquarium can be a challenging yet gratifying hobby. You can create a thriving underwater ecosystem in your home by carefully selecting the right equipment and marine life and diligently maintaining your aquarium.

It takes time, patience, and research, but the result is a beautiful, living piece of the ocean you can enjoy and be proud of.