How to setup a Reef Aquarium

Setting up a reef aquarium is a more advanced form of aquarium keeping that requires a bit more knowledge and equipment. However, with proper planning and care, a reef aquarium can be a beautiful and fascinating hobby. Here are the steps to get started:

1. Choose the right size and type of aquarium:

A reef aquarium typically requires a larger tank, with a recommended minimum size of 100 liters.

It is always easier to maintain stable parameters in a bigger tank and stability is the key to successful reef keeping. Alternatively, owning a nano tank is a good and more affordable way of deciding whether reef keeping is really your thing.


It's important to choose a tank that has a strong enough filtration system to support the delicate reef environment.

2. Pick a location:

Like with any aquarium, choose a flat surface that can support the weight of a full aquarium. Keep in mind that an aquarium filled with water can weigh a few hundred kilograms.

make sure it's near a power source and has access to a water source. Reef aquariums are best kept away from direct sunlight, as this can promote algae growth.

The tank inhabitants need some peace too, so it's typically best to set the tank up in a quieter place.

3. Purchase and set up the necessary equipment:

A reef aquarium requires:

  • Strong filtration system
    Most reef aquarium systems are equipped with a sump. This system is ideal for reef keeping as it has plenty of room for your equipment and biological media. It is also very easy to maintain.

  • Protein skimmer
    The protein skimmer removes excess proteins from food leftovers and other substances that should be regularly removed from the water. This device effectively replicates the natural process of the ocean producing sea foam in order to rid itself of waste.

  • High-quality light source
    To make sure the fish and the photosynthetic corals get enough light.
    A reef aquarium requires a specialized light source that provides the right spectrum and intensity of light for coral growth and health. Most modern reef lights are LED.

  • Heater
    To maintain the optimal temperature of your reef. Depending on your local climate, or which species you are keeping, you may also have to look at getting cooling fans or a chiller to maintain the temperature if it starts to rise too high.

  • Thermometer
    A thermometer is highly recommended to make sure your heater is working correctly, and that the temperature isn't rising during summer.

    A thermostat is a similar tool, but can directly control your heaters and cooling devices to maintain a constant temperature. Most thermostat devices are also equipped with beeping alarms so they are a good early warning safety device in case something does go wrong with your heating or cooling.

We also recommend net covers, as they can help prevent some fish from making unwanted trips outside of your aquarium and onto the floor.

4. Create some living space:

This is the creative phase where you can use quality rock that will create a good environment for placing your corals and also for bacteria multiplication.

Rock is a critical component of a reef aquarium, as it provides a natural habitat for beneficial bacteria, and a surface for corals to attach to. You can arrange the rock to create a natural-looking reef environment, and add other decorative elements such as sand, shells, and caves.

We recommend avoiding using live rock as this can introduce a vast array of unwanted pests that may negatively affect your reef-keeping experience. Any dry rock you add will eventually become live rock in your aquarium over time.


Once satisfied with the rock layout, fill the bottom with aragonite sand. It may be beneficial to also use some bio-sand to help populate the tank with nitrifying bacteria.

5. Mix your saltwater

Before filling the aquarium with saltwater, it is often a good practice to check the system for tightness by using freshwater.
If adding salt directly to the aquarium, never add more than 1kg at a time as there is a thermal reaction that occurs and may damage the aquarium.

Invest in some water storage drums or pickle barrels to mix your saltwater outside of the aquarium.
Fill your container with Reverse Osmosis (RO) water, or water with low hardness. RO water gives you the most control over your reef as the only minerals in the aquarium are the ones you have added.

Add your salt to the container.
You should be aiming for a salinity of 1.025s.g., or 35ppt.
35ppt means that for every thousand grams of freshwater you should add 35 grams of salt per litre of water.
1000g = 1kg = 1000ml = 1 litre.

Always refer to the mixing instructions for your brand of reef salt.

Once you've added your salt, set up a pump or wavemaker to continuously stir the water until you are ready for use. You typically want to let your salt mix for between 8 and 24 hours. This makes sure the salt has fully mixed.

Always measure the salinity of your water before use.

As water evaporates, the salts and minerals remain. Use freshwater to top off any evaporation from your aquarium.

6. Cycle the aquarium

Just like with a regular aquarium, it's important to allow the nitrogen cycle to establish in the tank before adding any coral. This can take 4 to 6 weeks. You can use a water testing kit to monitor the levels of ammonia, nitrite, and nitrate in the water.

Boost tank maturity by using a bacteria supplement to help establish nitrifying bacteria.

Using a phosphate-removing resin when setting up a new aquarium can greatly improve the clarity of the new tank. The resin will absorb phosphates and silicates from the water which will help reduce algae growth during the initial stages of the aquarium cycle.

If after 4 to 6 weeks the water shows no ammonia or No2 presence, we can add our first livestock. The most important thing to add is the clean-up crew to the aquarium.
As long as there are no animals in the aquarium, the main parameters can be raised without limits if they are not in range.
Firstly, add snails, crabs and shrimp. It is also advised to feed the clean up crew from time to time.

It is important to keep the No3 and Po4 levels low. This will keep the tank free from unwanted algae growth.

7. Introduce your stock:

Once the nitrogen cycle is established, you can start adding your coral to the aquarium. Introduce them gradually, and make sure the water temperature, pH, salinity, kH, Calcium, Magnesium, and light levels are suitable for them.

Maturing aquariums often struggle with diatom blooms. It is completely normal and shouldn’t be worrying. After the diatoms disappear and the first corals have been successful and are extending polyps, the aquarium may be further stocked.

Before introducing decorative fish, start with corals.

If all the parameters look fine, think of easy species like: caulastrea candy cane, sinularia, pseudogorgonia, euphyllia, seriatopora callendrium, seriatopra hystrix, stylophora.
If the goal is the keep an SPS tank, avoid introducing soft corals as they are expansive and have different requirements than SPS corals.
After the corals acclimate, start feeding with coral foods and supplements.
When a few weeks pass, if everything looks fine and healthy, start slowly introducing decorative fish. Things like clownfish, gobiodon, cardinals, and tangs are safe to introduce to a young tank.
After more time, more difficult and demanding corals and fish can be introduced.

A good clean up crew population is critical in keeping a clean reef tank.
Good clean up animals are:
Snails, like trochus snails and nassarius snails.
Crabs, like emerald crabs and hermit crabs.
Shrimps, like peppermint shrimp, blood red fire shrimp.

Remember, each type of coral has its own specific requirements, so it's important to research the species you want to keep and provide them with the appropriate environment. Also, be prepared to invest time and money into maintaining the reef aquarium, as it requires regular water changes, testing, and equipment maintenance.

For further reading, check out our guide on Keeping a Reef Tank.

Coral Safety

Palytoxin can be found in some ornamental coral and can be dangerous to your health. Take precautions when handling marine corals and live rock.
Some Zoanthid coral species popular with marine aquarium enthusiasts can contain Palytoxin. This toxin is dangerous to your health and being exposed to it can have potentially life-threatening consequences.
To avoid exposure:

  • Keep the general handling of corals to a minimum.
  • Avoid handling soft corals and live rock with bare hands.
  • Always handle coral underwater. Bag rock and coral away from aquarium lightning and seal the bag before removing them from the aquarium.
  • Monitor aquarium water levels and ensure coral is completely submerged at all times.
  • Avoid any coral maintenance activity that can potentially produce aerosols. eg. Scrubbing, breaking, cutting, scraping, brushing, and particularly using boiling water or chemicals.
  • Avoid placing coral under powerful halide lights when out of the water. Halide lights used to sustain and raise coral colonies can cause heat stress in corals that are out of the water causing a rapid release of Palytoxin.
  • Avoid splashing and dispose of aquarium water carefully that may contain Palytoxin.
  • Remember that Palytoxin can travel some distance in water aerosols.
  • Be aware that Palytoxin is heat stable – heating does not remove the toxin but it can be deactivated using bleach.