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Ready to take on the challenge of starting a saltwater tank? Don’t worry, we’re here to talk you through every step of the way.

The truth is, saltwater isn’t much more difficult to maintain than a freshwater tank, especially if you don’t plan on keeping any demanding corals. The other half of the coin, however, is that saltwater is much more expensive to get going and maintain.

A successful saltwater aquarium is more than worth the cost, though, if you’ve got your heart set on it.

Read our guide below to find out everything you need to know about preparing your first saltwater aquarium setup and how to maintain it.

Step 1: Planning Your Saltwater Aquarium

In order for your saltwater aquarium to succeed, you need a plan. We understand, of course, the eagerness to set up your tank as quickly as possible, but going in blind is a sure way to overspend with a rocky start.

Instead, take a couple of weeks to a few months to research exactly how saltwater aquariums work: nutrient import and export, fish compatibility, the different types of filtration systems available, what type of tank you’ll use, and other pieces of aquarium equipment you’ll need.

The possibilities for saltwater aquariums are endless, and you need to decide what you want based on knowledge, budget, and dedication. 

Location

Before choosing what type of fish you want to keep, you need to think about where you’re going to place your new aquarium.

There are a few things you want to get in order before placing a large, many-gallon saltwater tank system on your floor:

Make sure your floor can support the weight

This is especially important if you plan on setting up a larger tank. On average, one gallon (3.8 L) of freshwater is 8.3 pounds (3.8 kg); saltwater weighs slightly more.
Add in the glass aquarium, stand, substrate, filtration, live rock structure, and you have a significant amount of concentrated weight. Keep in mind it is also better to keep your display tank perpendicular to floorboards for level weight distribution as opposed to parallel.

Keep away from windows

 If you like having your curtains or blinds open, then don’t place your aquarium in front of a window. This can lead to excess nuisance algae, locking you in a never-ending battle. If you have no other option, try to keep the blinds down as much as possible and add a background to the aquarium. 

Near electrical outlets

You will find that saltwater aquariums require much more power than freshwater tanks. Be prepared to have a surge protector or power strip constantly attached to your wall. Keep in mind that this will also result in a higher electrical bill.

Keep away from bright lights and loud noises

 You want your saltwater fish to be active, right? Bright white lights and loud noises can scare them and keep them hidden in the back of the tank. Try to make your tank a centerpiece without having too many other distractions nearby.

Easily accessible

Lastly, you want your aquarium to be easily accessible. This means being able to work in and around the entirety of the tank. Be prepared to do weekly water changes and cleaning. If you have tile flooring, this can help keep away salt creep and subsequent erosion from aquarium water.

Once you’ve found your personal preference of location, it’s time to install the tank. Whatever display you end up going with, it’s recommended to do a dry trial run first before you fill the tank with water.

A dry trial run entails leaving the tank fully set up for a couple of days. This should allow you to see how it fits in with the life around it, like if it’s in the way of daily activities or just much bulkier than you originally thought. 

Remember, there’s no rush to fill up the tank as soon as you get it!

Choosing an aquarium

After you’ve found the perfect location for your aquarium, you need to figure out what the best aquarium is for you. 

Quick note in regards to aquarium size: many new saltwater aquarium hobbyists are told that bigger tanks are easier than small ones. While this is true when it comes to maintaining water parameters, bigger tanks are much more expensive. Plus, not everyone has the room.

The truth is that small, or nano, saltwater aquariums can be just as easy as larger ones if given the right consideration. It’s a process to configure your ideal tank, so don’t feel obliged to take on something you’re not prepared for!

The most important things to consider when choosing an aquarium are budget, livestock, and longevity.

Budget

As with anything, fish tanks can be as top-of-the-line or as discounted as you are willing to pay. If you do it right, it can be a relatively inexpensive hobby. When it comes to picking out a marine aquarium though, we definitely recommend spending a few extra dollars for security.

Reputable glass aquariums are fairly affordable, and it’s worth it just to avoid the worry of constantly checking the tank for leaks. The same is true for an aquarium stand, which is usually significantly more expensive than the tank itself. Again, with a piece of equipment this important, it’s worth spending more.

But whether you prefer glass aquariums, acrylic tanks, square or hexagonal ones, you want to make sure it will hold under the pressure of water. You also want to make sure your stand can take the weight and won’t corrode when in contact with saltwater.

Like with freshwater counterparts, it is strongly recommended to fill up the tank for a few days beforehand to make sure it does not leak. If you find it does leak, there is a wide range of aquarium sealant products available at most pet stores to patch up any leaky spots.

Size

Given your budget, you need to decide what size tank you want.

In general, larger marine tanks are easier as they keep water parameters more stable and allow for a healthy range of fish and invertebrates. However, smaller tanks have a lower start-up cost and can be just as rewarding as bigger ones. 

After all, you can always make a simple tank pop with the right aquarium lighting and decor.

That being said, we should note that most hobbyists choose to upgrade within the first year of joining the saltwater aquarium hobby, so maybe go for the bigger tank if you’re really in between the two.

Livestock

Now, the fun stuff. How will you stock your saltwater aquarium?

Marine fish need a lot more space than freshwater species, and a larger tank will allow for, well, bigger options. There are three main options you have for stocking your saltwater aquarium: fish-only (FO), fish-only with live rock (FOWLR), or a reef setup.

Fish-only tanks

A fish-only saltwater aquarium is the easiest to set up, but not one of the most natural. These aquariums are similar to freshwater setups with simple filtration, an aquarium heater, and artificial decorations.

Fish-only aquariums focus on just that, the fish. These tanks are good for beginners who might not know too much about the saltwater aquarium and have a limited budget.

Given the tank size, all compatible fish can be kept together; this setup is most common when keeping aggressive species that would otherwise pick at rock and certain types of corals.

Some grazers, like tangs, will need extra algae supplements as they can’t pick at the live rock all day.

Fish-only tanks with live rock

Live rock is the foundation of a natural and successful saltwater setup. This type of rock setup provides surface area for beneficial bacteria to prosper and for microfauna and flora to flourish. 

FOWLR tanks are almost the same as fish-only setups but focus more on giving your fish a natural ecosystem. Some challenges, like pests, hitchhikers, and rock maintenance, arise with setting up a FOWLR tank, though you can seed dry rock with the live rock to help prevent infestation.

There aren’t any limitations regarding fish in a FOWLR tank — all compatible species can be kept. Tangs, butterflyfish, and angelfish will especially appreciate being able to graze on any food available in the nooks and crannies of the rockwork. 

There are some species, like parrotfish, who may chomp away at the rock, but others will call it home. FOWLR tanks are also much easier to convert into a natural reef tank setup than FO systems. 

Reef tanks

Whether you plan to or not, most saltwater hobbyists end up owning coral(s) at some point in their tank’s lifetime. 

Reef setups take the most planning, and usually the most money. Instead of only needing to keep fish happy and healthy, you are catering to an entire ecosystem. Despite the additional equipment and aquarium maintenance required, though, it doesn’t need to be much more difficult.

There are many different ways to set up a reef aquarium. You will need to decide if you want to keep small polyp stony (SPS) corals, large polyp stony (LPS) corals, soft corals, or a combination of all of them in a mixed reef. Some hobbyists even choose to keep macroalgae tanks.

No matter the type of reef setup, your fish choices greatly diminish once you bring corals into the picture. Some of the most well-loved but less hardy fish and invertebrate species are not reef-safe and can’t be kept in reef tanks.

It is relatively important to decide early on if you’ll eventually want corals in your tank. That way, you can make sure to buy reef-safe species from the beginning.  

Filtration

Now that you have a sense of how big your tank will be and how many fish and/or corals you want, it’s time to think about filtration. Unlike freshwater aquariums, filtration is almost completely necessary for a successful tank.

Contrary to popular belief, there is little major difference between the types of filtration available. Still, each requires extra maintenance to be done, and each offers something slightly different, too.

In general, the three main filtration systems available for saltwater aquariums are “hang-on-the-back” (HOB) filters, canister filters, and sump filtration.

HOB filters

HOB filters are tried and true for freshwater aquariums, but how do they stand up for something as complex as an SPS-dominant reef?

Just fine, actually. HOB filters are designed to house filter sponge or floss and some activated carbon. This offers enough room for biological filtration by a colony of beneficial bacteria as well as some chemical and mechanical filtration through various media.

In essence, the combination of a biological filter and chemical/mechanical filters is all that’s needed to successfully run a tank. 

Canister filters

Canister filters are in between HOB filters and sump filtration. The appeal of canister filters is that they are external, hold a lot of media, and don’t need to be cleaned often.

Saltwater tanks require more extra equipment than freshwater ones, so hobbyists have a goal to make pumps and wires as invisible as possible. A canister filter can be neatly stored underneath the setup, which frees up real estate in the display tank.

Canister filters also hold much more media than HOB filters, which can be appealing for those with a larger bioload. This media also doesn’t need to be cleaned as regularly, which can dramatically cut down on costs and maintenance time.

Sump filtration

Sump filtration is the most common type of filtration for saltwater aquariums, but not at all necessary. The benefits of sump filtration are space, customizability, and external storage.

Sump filtration is made from chambers. These chambers can be used for multiple purposes, like storing protein skimmers, having an auto top-off reserve, housing a refugium, and adding even more media. 

These filters remove nearly all excess equipment from the display, are easy to maintain, and effectively offer mechanical, biological, and chemical filtration. In addition, their return nozzles can be used as an additional source of water flow. 

Substrate

One of the last things to consider is the substrate. Though you might not think substrate is a big deal, it is pretty important in the saltwater world.

There are three main substrate options you have available to you: crushed coral, sand, and bare bottom.

Crushed coral

Crushed coral is exactly that, small pieces of coral skeleton, as well as other pieces of shell and rock.

This substrate is very coarse which can lead to trapped detritus and coralline algae. Crushed coral can also have sharp edges which can make it difficult and unsafe for bottom-feeders, like gobies and blennies, as well as other corals and invertebrates.

On the other hand, coral sand has much more weight to it and isn’t blown around the tank. This makes distribution even and can help weigh down rock and corals. 

In freshwater aquariums, crushed coral is popular for cichlid setups as it helps raise pH. This is true for saltwater as well, though many hobbyists control pH through their salt mix instead.

In general, crushed coral is outdated, though some hobbyists still love it. 

Sand

Sand is the most popular type of saltwater substrate right now, namely aragonite sand. This fine-grained substrate makes reefs look completely natural while being safe for fish and invertebrates.

Because the sand bed is so fine, it can be difficult to vacuum. It is also easily blown around the tank by powerheads and other equipment, which can leave portions of the bottom glass exposed. 

Aragonite sand will also raise pH. 

Barebottom aquarium 

Barebottom aquarium setups have become more popular over the past few years. This setup means using no substrate at all and instead, placing rocks and corals directly on the bottom panel of the tank.

Of course, this can be a little scary as rock could potentially fall and break the glass. As long as the rock structure is secured though, there is little reason to worry.

Bare bottom setups offer a few benefits, too. For one, it makes cleaning extremely easy and keeps the need for vacuuming at a minimum. It is much easier to get adequate circulation throughout the tank without having to worry about sand getting kicked up.

However, the bare bottom is not the most natural look, and you may need to make special arrangements for substrate-dependent species, like wrasses, gobies, and other bottom-dwellers.

Testing equipment

Last but not least, you will need a saltwater test kit for testing water parameters. You will most likely need to buy a refractometer separately. 

It is always recommended to purchase a refractometer instead of a hydrometer as they are more accurate and long-lasting. Though refractometers might be more expensive and look more complex to use, they are very easy to read and are usually a one-time expense. 

In addition, you will need saltwater test kits for:

• Ammonia
• Nitrite
• Nitrate
• pH

If you plan on keeping corals, then you will also need additional test kits for:

• Alkalinity
• Calcium
• Magnesium

Don’t forget to pick up a thermometer too! 

Step 2: Setting Up Your Saltwater Aquarium

Once you have your tank picked out with all equipment installed, it’s time to fill it up. Just like freshwater aquariums, marine aquariums need to go through the nitrogen cycle. 

Before you start to cycle your tank though, you need to know how to make saltwater! 

Mixing saltwater 

Mixing saltwater can be a little confusing at first, but it gets easier over time. You’ll need your refractometer for this.

The recommended salinity, or salt concentration, for a saltwater aquarium is between 1.022-1.026. To make saltwater in this range, simply add marine salt mix to freshwater in a bucket in small increments. Mix until the salt crystals are fully dissolved and test the salinity.

If the salinity is above the ideal range, add more freshwater. If the salinity is below the ideal range, add some more salt until it’s in that range. 

When mixing saltwater, don’t forget to use a water conditioner to remove chlorine and chloramines! You can also find pre-mixed saltwater, but it’s much cheaper to mix your own.

Cycling

Once your water has been mixed, it’s time to start the cycle. This is very similar to cycling a freshwater tank, though you will need to stay on top of evaporation to keep the salinity stable.

Salt doesn’t evaporate from water, so more evaporation means saltier water. This can be fixed by regularly topping off the tank with freshwater. Don’t worry, you’ll quickly pick up a schedule for topping off your tank, or you could choose to install an auto top-off system along the way.

As with freshwater, there are many ways to start a saltwater aquarium cycle. One of the best ways is to introduce filter media or another bacteria population into the tank from an established system. This is most commonly done through filter sponges or live rock. 

If you have access to filter media or live rock from a pre-existing saltwater tank, then you have the foundation for a bacteria population that greatly shortens or even eliminates the need to cycle the aquarium. If you don’t have anything like this though, you’ll need to cycle the tank from the beginning.

The most common ways to cycle a saltwater aquarium are:

1. Dosing ammonia and regulating water parameters
2. Using a bacteria start-up supplement
3. Introducing live rock and letting the die-off trigger an aquarium cycle

Once started, you will see ammonia levels spike, return to zero, then nitrite levels spike, return to zero, and then nitrate levels spike. At this point, it is best to do a large water change. Shortly after, your aquarium will be ready for fish and invertebrates. 

Like freshwater, this process can take anywhere from 2-6 weeks. There is no true way to speed it up, and it should not be rushed.

Stocking and quarantine

Once the aquarium is fully cycled, it’s time to think about stocking again. 

When dealing with saltwater systems, it’s highly recommended to have a quarantine tank setup as well. While many freshwater diseases and illnesses can be treated by increasing water temperatures and making other small changes, marine infections are much more difficult to eradicate.

Not only are marine diseases and illnesses more difficult to treat, but the cost of each fish and invertebrate is much greater, too. To avoid a hit to your wallet, you want to do this right the first time.

Most hobbyists choose to go with a hardy saltwater fish, like damsels, to start their tank. Clownfish are a good starter, though other damsel species can be aggressive and claim the tank as their own — not great when you’re trying to make a community tank.

Chromis are also a popular starter fish, though they are incredibly aggressive and often seem to die overnight with no explanation.

Besides clownfish, other good alternatives would be gobies and blennies. Like in freshwater tanks, you want to add in order of aggression from least to greatest. With saltwater, you will also want to add from least sensitive to most sensitive to prevent diseases from entering the system.

Having a quarantine tank will greatly reduce the chances of illness entering the system. On average, fish and invertebrates should be quarantined for at least 2 weeks to monitor their health before joining the saltwater aquarium setup. 

Clean-up crew 

In order to keep your aquarium running as a stable ecosystem, it’s important to establish a saltwater clean-up crew. There are many options to choose from and it’s important to know the role that each species could play in your tank.

Hermit crabs

Hermit crabs are fun to keep, and they are great scavengers. They feed mainly on meatier, leftover foods, but have been seen picking at algae (or corals) from time to time.

They are constantly molting and growing out of their shells, so make sure to have extras on hand. Hermit crabs are also advantageous and kill snails for their shells if need be. 

Though hermit crabs are popular with beginners, many experienced hobbyists avoid them for herbivorous alternatives. Hermit crabs can also damage corals if they walk over them and scrape them with their heavy shells. 

Snails

Snails are the most popular option for reefers as you usually don’t have to worry about them going after corals or fish. Snails can also go up and down the glass to clean algae — a physical skill hermit crabs lack.

There are varieties of marine snails, some better than others. Some snails live in the sand, others can’t flip themselves back over if they fall, and then there are those that prey on other invertebrates.

Each snail has its place in the aquarium and can be beneficial, depending on the setup. 

Shrimp

Shrimp are another popular member of the cleanup crew, even though they can create as much of a bioload as small fish. 

Yes, shrimp will graze on the rocks and might even help take care of some pest anemones, but they won’t rid your aquarium of algae. Sorry, they’re not window cleaners.

Some species of shrimp will help keep your fish clean of parasites, though!

Other cleanup crew options

Nudibranchs, sea urchins, and starfish are invertebrates a little more specialized than hermit crabs, snails, and shrimp, and will do better in a tank that fits their needs. 

Adding corals

After about 3 months of successfully having a running saltwater aquarium, you can begin thinking about corals. This delay should be enough time for the tank to begin to stabilize and for tank maintenance to become routine.

In general, soft corals are recommended for beginner hobbyists. Here are some of the most popular beginner corals:

• Green star polyps
• Pulsing xenia
• Mushroom corals
• Leather corals (toadstools, Kenya tree corals, colt corals)

Eventually, you may add large polyp stony (LPS) corals, like hammers and frogspawns. At that point, you may also consider adding an anemone if space allows.

Once the tank has reached about one year in age, you may start experimenting with small polyp stony (SPS) corals.

Do not be discouraged if your corals die. Even in perfect tanks, corals are bound to die for no clear reason at times. Maintain parameters, deal with algae, and have patience and your reef will slowly start to grow over time. 

Step 3: Maintaining Your Saltwater Aquarium

Setting up an aquarium is fun, but the work and expenses don’t end there. As mentioned before, maintaining a saltwater aquarium isn’t as hard as you might think. For the most part, it’s the same as a freshwater aquarium, just with a few additional steps. 

Water changes

Water changes will need to be done weekly, biweekly, or monthly, depending on how the system runs.

It will take a while to understand how nutrients move through your system, and the frequency of water changes will mainly depend on salinity, nitrate, and phosphate levels; if keeping corals, then you will also need to watch alkalinity, magnesium, and calcium levels as well.

From day to day, salinity is one of the most important parameters to keep track of. Evaporation causes salinity to increase and freshwater needs to be added regularly to maintain parameters; water changes will also help control salinity as well.

During water changes, it is strongly recommended to vacuum the substrate and use a turkey baster to get debris off rocks. Remove about 25% of the water and add newly mixed saltwater back. 

Equipment maintenance

Along with general tank maintenance, you will need to keep on top of emptying out your protein skimmer and cleaning other pieces of equipment when needed. 

In general, it is recommended to clean powerheads, nozzles, and other devices every 3-6 months to prevent algae buildup and malfunction. 

Algae

Next to maintaining water parameters is dealing with algae. Algae is always a headache, and it’s bound to happen to your aquarium within the first few months. New saltwater aquariums are especially susceptible to diatom outbreaks. 

Water changes will help deal with algae, but this is why a good marine clean-up crew is necessary. When buying a clean-up crew, make sure that the invertebrates are herbivores; though a hermit crab might seem fun, they’re much better at scavenging for meatier leftovers than picking at algae.

Dosing

If keeping a saltwater aquarium, you may need to dose for certain parameters. This usually includes alkalinity and calcium, though you might need to add magnesium, phosphate, and other trace elements as well.

Dosing is required when parameters change too much between water changes or when water changes are failing to maintain those levels. This is due to corals and invertebrates using those nutrients for growth and natural processes, which need to be replaced with supplements.

Nutrient deficiency can quickly happen in heavily stocked setups, especially those with SPS corals that need to grow calcium carbonate skeletons. This can lead to stunted growth and an unhealthy system.

Dosing might seem hard at first, but it’s relatively straightforward and becomes easier as you learn how your tank operates. The key to dosing is regularly testing water parameters.

In order to know if you need to dose your aquarium or not, measure parameters daily in between water changes. If you have a significant amount of corals, you should see some decline in alkalinity and calcium, and possibly other nutrients; this decline will largely depend on the number of corals being kept and their nutrient requirements.

Once you are able to see how nutrients are being used in the aquarium, you can measure the dosage for each of those nutrients to keep them stable. Aquarium brands have also invented convenient automatic dosers which can be helpful if dealing with a large, biodiverse system.

Adding livestock

Of course, your tank will become a living thing that you’re constantly giving and taking away from. Again, you want to have patience when adding new livestock.

Like before, it is strongly recommended to quarantine new fish and invertebrates. This is especially true for established tanks as it can be a real pain to catch fish and move them to a hospital tank. 

It is also recommended to either quarantine or dip new corals that you add into the tank. Corals are notorious for introducing pests and hitchhikers into the aquarium, like Aiptasia. You will want to prepare your livestock as much as possible to be seamlessly acclimated to the display system.

Conclusion

Setting up a saltwater aquarium can be daunting and expensive. It takes about a year to get comfortable with how your tank runs and for fish and invertebrates to completely settle in. 

If you’re on the fence about making the switch from freshwater to saltwater, though, don’t let that deter you! A marine setup is truly special and can’t be compared to anything else in the hobby.

If you have any questions about setting up a saltwater aquarium, maintaining fish tanks, or have had experience setting up the marine system of your dreams, don’t hesitate to leave a comment below!

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