What Is A Refugium?

Refugiums go unnoticed by far too many new aquarists. The difficulty of set up and maintenance sounds so overwhelming that those who do learn run away without learning more. In truth set up is none too hard and can be done within an hour. The benefits are so plentiful that adding one to your aquarium should not be over looked. Read on to discover the many benefits of refugiums and even learn the set-up process, tips on helpful arrangements and how to create the most value for your aquarium.

A dragonet, who's survival depends on a fully functional refugium

So What Is A Refugium Exactly?

Simply put, a refugium is a separate body of water from the main tank that acts as refuge for multiple life forms. These range from amphipods, copepods, phytoplankton, brine shrimp and countless other things that would quickly be hunted to extinction in the display tank. Many tank inhabitants actually depend on these small creature as a food source. If you would like to keep corals, dragonets or macro algae a refugium is an absolute necessity

What Are The Benefits Of a Refugium?

Many owners may wonder why they wouldn't want a separate tank. In truth you can breed these small creatures in another tank if you are willing to delve into the art of culturing populations. However by leaving the display tank connected to your refugium you gain so many benefits:

Which Type Of Refugium To Use

The three main types of refugiums are hang on back, in tank and in sump set-ups. Each has their own benefits and drawbacks, all of which we will discuss further

In Sump Refugiums

These are the biggest and strongest set-ups. If you pay a visit to any specialty fish store you are bound to see them. Sumps are large containers of water, usually either plastic tubs or long glass aquariums, that take water from the display tank and run them through a series of chambers before returning the water. The biggest chamber in these set-ups will be the refugium.

The main benefit to this choice is simple. Power. With such a large size aquarium owners are able to grow large colonies of copepods to feed their fish, grow and harvest plenty of algae keeping the tanks crystal clear and create a near self sustaining environment. If you have the time and space we strongly recommend you use this design.

The main drawbacks of this set up are its cost, set-up and space requirements. If you have a 20 gallon in your bedroom you likely do not need a 40 gallon sump as well. Those with massive 300 gallon displays however will find the sumps small and easily placed. The price of the sump lies in the pumps and siphons used to move water between the bodies of water. Lastly the set-up of a sump is actually fairly difficult. Most users fail their initial try, which can seem like a huge waste of money. Through perseverance you can build these successfully, or outright buy one if you have the spare money.

Cost:$80 to $600 depending on if you DIY or buy

Hang On Back Refugiums

These are the simplest and more common choices of the three. Hang on back refugiums are almost identical to HoB filters. In fact many DIY refugium designs use old filters as a body.

Installation is simple as you place the refugium on your tanks rim and start up the power head that moves water between the tank and refugium. Quick and easy.

The downsides to this design would be the size and placement of the refugium. These will not be big enough to support a tank on their own with live food. Unless you buy the smallest possible refugium you should be able to create and successfully use your algae scrubber, but you may not see much benefit from your macro algae.

Overall this will remove most algae from the tank and give you a fair supply of live food.

Cost: $30 to $100

In Tank Refugiums

These are almost exclusively used for breeding live foods, fry and macro algae. They are simple in tank containers that allow free water movement but still keep out fish and invertebrates.

These hold the benefits of being the easiest to install, not taking up any additional space and have one of the lowest costs. For set-up and installation place your copepods/fry and macro algae in the refugium and affix it to the side of your tank. No need for circulation makes these very affordable.

The downsides are that they cut into your tanks space and can have no lighting schedule of their own. For massive tanks losing a few gallons may be nothing, but cutting into a 35 gallon will be hard to ignore. Likewise there will be very little algae removal coming from the in tank refugium. Algae scrubbing is a difficult and still possible process, but you will not see the same level of clean the other set-ups will give you.

Cost: $15 to $40

Populating Your Refugium

No matter your choice in refugium there is always the decision of picking the most helpful inhabitants.

Live Foods
These can be brine shrimp, copepods, amphipods, feeder fish and even plants. The main benefit here is that we can enrich their food. By feeding the brine shrimp and pods what we want the fish to eat, we stuff their new live food with the nutrients they wouldn't want otherwise. Most marine Tank owners will use refugiums as a chance to supply their tanks with pods, sustaining small hunting fish as well as the bigger fish. Frozen brine shrimp are available in most pet stores but offering our fish the real deal is a treat that really gets them excited.

Macro Algae
While many shape and sizes exist we always point new owners to chaeto, a dense green plant that saves on space and grows quickly.

We've all heard the horror stories and some of you may have witnessed it. When we supply our main tanks with too many scavengers they can actually gang up and take down our fish! without forsaking them from our homes, we can place them into our refugiums, allowing them access to clean out our tanks to a lesser extent while keeping our fish safe.

Sometimes we may have to even remove the scavengers because our fish themselves will hunt them, making an expensive meal of our new underwater custodians.

Sand, Gravel And Live Rock
Both sand and rocks provide the above with homes, allowing better reproduction and feeding. Despite being in an enclosed area your pods and scavengers will still feel threatened if they are in the open, which is why we suggest at least one rock for them to crawl around. The substrate acts as a base that grows beneficial bacteria that increase biological filtration. The substrate can also hold food in place for the pods and scavengers to eat.

Refugium Maintenance, Guidelines And Hints

Keeping a refugium running is pretty simple. your first priority will be having the right amount of water flow. The commonly accepted rule is to change your refugiums water once per hours, meaning that if your refugium is 10 gallons, you should have a water flow of 10 gallons per hour. Most of these will be low easy to achieve numbers. The only high ones should be in sump refugiums.

Check your refugium daily to ensure their is no blockage, water flow is going freely and that their is not a dead zone on the bottom where waste collects. When water flow does not circulate the entire refugium the collection of trapped waste will rapidly decay and avoid reaching your filters, damaging your water parameters. Consider increasing water flow or redirecting it if you see this problem.

Consider adding a protein skimmer to your refugium. These remove excess organic materials from the water, reducing the nutrients that algae use to breed.

For in sump and hang on back refugiums be sure to check your connections and fastenings. Having your refugium fall of the back of your tank or sump disconnect while you are away from the home can lead to some serious water damage. Give them all a small bump when first installing to ensure they do not fall easily and keep your connections tight.

As with your main display tank, buy the biggest refugium you can fit and afford. while you may be satisfied now, spending an extra $10 will prevent you from having to buy a new set-up should you want to move to a bigger size. We all know the allure a new fish can have on us, so get the extra water volume while you can.

After learning all the basic information about refugiums you are ready to decide if adding one to your aquarium is the right decision. Generally speaking, if your tank is over 50 gallons a refugium is a good choice. Whether you're using these in freshwater, saltwater or even brackish tanks you will be sure to see strong benefits from this new addition. If you make the decision to add a refugium, be sure to pick the right kind for your specific situation. Populate the refugium with the right objects and maximize your benefits.