Miniature Reef Aquariums, also known as NanoTanks are becoming increasingly popular as the space and investment required of a large reef aquarium are sometimes prohibitive. The Nano Reef aquarium is by no means any less substantial a venture than a large reef aquarium. The Nano reef aquarium must be carefully designed and spec'ed to function properly. The reduced volume of water will exaggerate any potential dangers of improper water chemistry or excessive organic waste. The Nano Reef aquarium is especially sensitive to instability in temperature, pH and excessive dissolved organics. A larger aquarium is more forgiving to changes, while subtle changes in a Nano Reef aquarium may be disasterous. With proper preparations and techniques however, the Nano Reef aquarium can be an outstanding example of a tiny slice of a coral reef. In this section of Reefs 101, we will examine a typical Nano Reef setup with a commonly used Nano aquarium, the 24 gallon NanoCube from JBJ Lighting.
The 24 gallon Deluxe NanoCube is an excellent choice for a beginners first Nano Reef aquarium. It is equipped with 2 x 36w Power Compact lamps and some models may have moonlights. This is sufficient to keep a large number of hard and soft corals, in fact only certain SPS corals and Tridacna clams may not be appropriate for this aquarium. The back of the aquarium features a built-in 3 stage filtration area. This is designed for a sponge in the first section, a bag of carbon and ceramic filtration media in the second and a 120VAC pump in the final chamber to return water back to the aquarium. Unfortunately there is no protein skimmer incorporated into the design and this may affect choices of coral to stock the NanoCube. For the reef aquarium, the ceramic media will do more harm than good, trapping organic particles and lowering water quality. So we will set up the NanoCube without the ceramic media and will also not use the included activated carbon. The included pump is a bit small for our taste and should be replaced by a more powerful model. The NanoCube also includes 2 x 60mm fans built into the canopy. This works very well at reducing moisture build-up in the canopy. One feature omitted from the design is the ability to run the fans without turning on the lights. This feature would allow the user to run the fans 24/7, not only keeping the canopy moisture-free, but also keeping the inside air fresh for efficient gaseous exchange. We will modify this feature later in the build of this Nano Reef aquarium.
Choose a Synthetic Sea Salt
The 21st century hobbyist has many choices in synthetic sea salts. In the last decade, the number of commercially produced products has grown to a dozen or so common offerings. Unfortunately most of these salts are inconsistent at best, often with different lots varying up to 20% in composition. We have had outstanding results from Oceanic Sea Salt, available in most finer aquarium stores. Saltwater should always be prepared in advance, allowing for complete dissolution and gaseous exchange. For a new aquarium build, I prefer a "specific gravity" of about 1.020. I like to use a pump or powerhead in my container to mix salt for at least 12 hours before use. The Nano Reef aquarium should be filled with saltwater and the pump started to confirm function.
Live Rock
The next step to starting a Nano Reef aquarium is to select live rock after filling the aquarium with saltwater. Again, the modern hobbyist has a vast variety of different live rock to choose from when building the reef aquarium. The Nano Reef hobbyist must always be aware of the size of the aquarium when purchasing live rock. Live rock should be selected on several attributes including size, shape, porosity, beauty and living organisms. The Nano Reef aquarium looks best with relatively small pieces with interesting shapes and textures. Live rock that has many small holes and openings will make the aquarium appear larger and will help it appear proportionate. Many hobbyists are quite excited about living organisms that may be visible on newly aquired live rock. Unfortunately, most of this life including coralline algae, sponges, macrolgaes, oysters, clams, worms and tunicates will not survive the project. After bringing the live rock home I suggest that you carefully remove the rocks from the box or bag in which they arrived and examine them. Carefully remove as much dying algae, sponge and whatever horrid smelling things as possible preferrably with a pair of tongs or tweezers. After this initial cleaning, clean the piece in a 5 gallon bucket half filled with saltwater, the same that is in the aquarium. Shake and swirl the piece of rock inside the bucket to remove as much loose matter as possible. Proceed to place all your rock into the aquarium after this cleaning, but don't worry about decoration or aquascaping at this time.
The next step could be called "conditioning" or "cycling" the live rock. Before the Nano Reef aquarium is ready for fish or corals, the live rock must be prepared by allowing and encouraging all dead or dying organisms to decay, break down and be carried into the water stream. The aquarium should be run with the lights off, but the pump and heater turned on. I recommend adding a second powerhead inside the aquarium, to aid circulation and water flow. The rear, lower corner is a popular location, either on the left or right. The dying organisms will pollute the water and may even pollute the air in the hobbyists aquarium room! The hobbyist will be able to see patches of white film or other visible signs of decay on the surface of the rocks. The water flow is critical to lift this off of the rocks and it may be neccessary to physically brush the rock to remove the dying matter. This is all normal and to be expected. After approximately 15-20 days, the water will be a very dirty appearing shade of yellowish brown. At this time, I like to prepare saltwater for a 100% water change. Be sure the saltwater is of room temperature or a bit warmer and has the same "specific gravity" or salt content as the Nano Reef aquarium. Using a siphon hose, I siphon off any sediment or detritus off of the floor of the aquarium, then siphoning the surface of the rocks themselves until the aquarium is empty. Then, quickly I refill the aquarium using a bucket, pouring the water vigorously over the rocks, trying to rinse and clean the rocks in the process. When the aquarium is full again, restart the pumps and repeat the aforementioned process for another 15-20 days. This time, the water will be much cleaner and will turn a much more pale shade of yellow. The surface of the rocks will appear much cleaner and the smell in the aquarium room should disappear. Unfortunately the beautiful purple, pink and green coralline algae may have disappeared and the rocks may look a bit bare. The aquarium lights should still NOT be run, as the light may prompt the growth of undesirable algaes as the water still contains many nutrients and organic waste. After the second 20 day period has elapsed, we will repeat this procedure for a final time, siphoning and cleaning in the process and refilling again. At this time I like to add some animals that will help in cleaning and caring for the live rock. Try some small reef-safe blue or red legged hermit crabs, approximately 2 per gallon of water volume. At this time, the lights may also be turned on, up to 2 hours per day.
Water Quality
For the first 2 months, the only water quality related checks will be the specific gravity, the amount of salt in the water and temperature. It is recommended to maintain specific gravity at approximately 1.018 to 1.022 during the initial live rock conditioning phase. The lower specific gravity will allow a bit higher dissolved oxygen, more gaseous exchange and encourage rapid bacterial cycling on the live rock. This is slightly lower than the normal recommended specific gravity of 1.023-1.025 once the aquarium has stabilized. The NanoReef aquarium is very sensitive to change in temperature because of the relatively small water volume. If the aquarium room warms during the afternoon, it's not uncommon to see a NanoReef aquarium spike up to 85F when the lights are on. The hobbyist needs to control temperatures as best as possible, primarily by making sure the hood is well ventilated, in the case of the JBJ NanoCube by two 60mm fans. In addition, the light cycle may be adjusted so that during the warmest time of the day, the lights are turned off. The NanoReef aquarium will also require a heater, not so much to keep the aquarium warm but to keep the temperature stable. Again, because of the relatively small water volume the aquarium may drop to 72F at night and rise to 85F during the day, this is much too large a temperature swing and is unhealthy for the aquarium and its' inhabitants. So in this case we will set the heater to 79-80F to minimize the temperature swing to 5 degrees. In this case it's still to warm, but it's more acceptable than the larger 10-15F swing. If possible, maintain temperature a bit lower, near 77F day and night.
The NanoReef hobbyist will need to purchase at least 3 test kits, one for Calcium, Alkalinity and pH. In addition, a Nitrite kit may come in handy to determine when the conditioned live rock is effectively eliminating/converting organic waste. Calcium is an important element, indeed Calcium is the "building block" of the reef aquarium. It is critical for the formation of a variety of structures, including the skeletons and shells of many corals, clams, algaes and other organisms. Calcium is present in natural seawater at a concentration of more than 400ppm. In the NanoReef aquarium I also reccommend keeping the Calcium at a level above 400ppm, even up to 450ppm. Alkalinity is equally important to maintaining a stable pH and working with Calcium for the growth and development of corals and aquarium organisms. Alkalinity should be maintained between 3.0-4.5 meq/L or 8-13dKH. Ph may be monitored either with an electronic pH meter or can be measured with a reagent based test kit. An unusually low pH may be dangerous in the NanoReef aquarium and should be maintained between 8.1-8.4.
Adding Corals
The first corals selected for the NanoReef aquarium should be small, hardy and inexpensive. One favorite is colonial polyps such as zooanthid's. They are compact sized, sometimes colorful and mostly hardy. One should avoid the temptation to add an expensive SPS coral or super-expensive LPS coral such as Acanthastrea. Sometimes the aquarium will simply be "out of balance" or have a "hiccup" with the equipment at the beginning and losses at the start are not uncommon.
Adding Fish
Many NanoReef hobbyists view fish as a liability to to the aquarium, but most of us desire the color, movement and interest that a select group of fish may bring to the tank. The selection of fish for the NanoReef aquarium must be made carefully. It is neccessary to choose fish that will be beneficial to the general well-being of the aquarium, preferrably one that is herbivorous and will help control nuisance algae without devastating populations of copepods and micro-organisms.
The First Month
After the first month of operation with corals or fish in the aquarium, it will be time for another water change. This time, the water change should only be about 20% of total water volume and should be mixed and prepared to match the NanoReef aquarium in temperature and specific gravity. At this time, it is permissible to add a small thin layer of substrate to the bottom of the aquarium for aesthetic reasons, but never more than 3/4" in thickness. In addition, make sure the lights are functioning efficiently by cleaning off the clear plastic splash guard with clean freshwater.
Maintenance
The NanoReef aquarium will need to be properly maintained to be an attractive, healthy, thriving aquarium. This consists of cleaning or siphoning organic matter that may be encountered in the aquarium and maintaining a stable water chemistry. The simplest and most effective method for Calcium and Alkalinity management in the NanoReef aquarium is Warner Marine Research CalxMax 2pt Calcium/Alkalinity Buffer. CalxMax is a 2-Part balanced ion supplement for maintaining calcium and alkalinity in all marine aquariums. Calxmax adds both calcium and carbonate alkalinity with major and minor elements by adding equal amounts of parts A and B. Calxmax will maintain calcium and buffer levels and end calcium - alkalinity instability.