by Holle Abee
Think of all the divers who go to such lengths to visit saltwater reefs for a view of the amazing sea life that inhabits the area. Now imagine that you can have a little corner of that magic in your own home. With a saltwater reef tank, you can have the mezmerizing tranquility and the brilliant natural beauty of a tropical sea, all vividly displayed in an aquarium.
A reef tank isn’t just a regular saltwater aquarium. The key word is “reef.” The main focus of the tank is the soft or hard corals. Colorful fish, sea stars, eels, anemones, urchins, shrimp, and sea horses can certainly be added, but everything should revolve around the coral itself.
To keep a healthy reef tank, certain guidelines must be followed to ensure the longevity of your corals. The other inhabitants of your tank will not be as sensitive as the reef, so again, its requirements should be considered first.
To begin, most experts recommend using reverse osmosis water – water that is forced through a membrane to remove at least 90% of impurities like nitrates, chlorine, chloramine, mercury, and copper. A reverse osmosis water filter will achieve the appropriate water required for your tank. Unfortunately, the process removes some beneficial minerals along with the harmful ones, but these can be added back with a good saltwater mix.
Hard corals produce stony exoskeletons that make up your reef. They come in a rainbow spectrum of colors and shapes. A few popular species include Acropora purple, blue, or green; pink Birdsnest; orange Montipora; yellow Porites; and the fascinating branched Staghorn. When purchasing your corals, packs with an assortment of species are available.
While soft corals lack the hard external skeletons of the hard corals, some may have “bony” internal parts. Popular soft corals are Mushroom, Xenia, Zoanthid, and Leather corals. The soft corals exhibit a wide range of bright colors and add movement to your tank, swaying gracefully in the underwater currents.
LIVE ROCK and LIVE SAND
Live rock is not actually “alive,” but it was once. It adds calcium and beneficial organisms to ensure prpoer water management. Available in branch rock and shelf rock, it provides the perfect place on which to set your corals. Purchase cured live rock, which has already been cleaned and conditioned and can be used right away. Live sand is basically the same as live rock – just in small particles.
There is much argument about proper temperature for reef tanks. This is partly due to the range of species kept in most aquariums. While many aquarists keep their reef tanks between 80-85 degrees, new evidence shows that 79 degrees inhibits metabolic activity and thereby decreases oxygen requirements and harmful waste products. You will need a chiller to maintain a constant desirable water temperature.
Nitrates, the waste by-products of bacteria that develop in the nitrogen cycling process, make a biological filtration system function. Too much is harmful to reef inhabitants and is the major cause of algae blooms. Healthy levels are between 0.25 and 5ppm, with less being better. Nitrates can be controlled with mangrove plants and nitrate reduction filtration. Tri-based pelletized carbon and RN! bacteria, manufactured by Hiatt, are used in combination to effectively reduce harmful nitrates.
Nitrates are generated by from the metabolic wastes of invertebrates, fish, and bacteria and are highly toxic to your tank. The level should be as close to zero as possible. Hiatt’s RN! and tri-pelleted activated charcoal will eliminate the harmful compound. Knowledgeable aquarists recommend using a charcoal-filled flow tube with your filtration system, making sure water and air flow freely through the tube.
pH (power of hydrogen)
Keeping a stable, proper pH level is critical in maintaining tank survival. The pH indicates the alkalinity or acidity of the water, with 7 being neutral. Above 7 is alkaline; below 7 is acidic. Saltwater tanks, because of nitric acids, carbon dioxide, and organic acids produced by natural wastes, tend to be acidic. The proper level, however, should be maintained at slightly alkaline, with 8.2-8.4 being optimum. Adding baking soda or a commercial pH buffer will return your water to the right level. Removing part of the water and replacing it and using a calcium reactor will help, too.
Another important mineral for your tank is calcium, at a level of 400-500ppm, which can be achieved by adding calcium supplements.
Sometimes confused with pH, alkalinity is actually carbonate hardness. The level in your tank is measured by the presence of calcium carbonate (CaCO3), which should be 150-200ppm. This is an essential compound for corals to produce their hard exterior and can be managed by adding commercial supplements.
Another important mineral for tank health, proper magnesium levels of 1200mg/L can be reached with epsom salts. For a 55-gallon tank, 90.8 grams should be added gradually over the course of 7-8 days.
Phosphate is one of the top trace elements in natural seawater, and of course, your ultimate goal is to re-create the normal environment of your reef and its inhabitants. A proper level is 0.05ppm. Use a reliable test kit to check your water. Phosphates are often found in foods, activated charcoal, and buffers, so your problem will be lowering levels, not increasing them. Use a limewater or kalkwasser solution to lower harmful levels, or try a commercial product like Coralife’s phosphate remover or Kent Marine’s phosphate sponge.
This refers to how much salt is in the water. Natural seawater ranges from 1.024-1.025, so you want to maintain this level in your tank. Use a hydrometer to measure your water’s salinity. The swing-arm models are easier to use, but remember: this is an important investment for the survival of your tank. You want a quality hydrometer that will give consistent correct readings, so don’t purchase an inferior one because it might be cheaper. If your salinity is too high, just remove some of your tank water and replace it with fresh. If the salinity is too low, add DISSOLVED aquarium salt.
Yet another inportant compound naturally occurring in ocean water is iodine, at 60 parts per billion. Your tank level can be increased by adding lugol’s solutions or by adding inexpensive potassium iodide (KI).
You’ll need a reliable test kit to achieve and maintain a healthy tank. Many experienced aquarists recommeng Kordon’s Aqua Tru.
A natural reef feeds from tiny food particles carried by constant ocean currents. To mimic these in your aquarium, place several powerheads around the tank to create turbulence. The movement also helps your filtration system remove detritus and uneaten food, inhibiting their breakdown before they can negatively effect the quality of your water.
To help prevent a multitude of problems, remove about 25% of your tank water and replace it with a fresh supply once a week. This might seem like a lot of trouble, but in the long run, it’s definitely worth the effort.
Now for the fun part! Colorful fish and other creatures will add interest and activity to your tank. Just remember the mayor of your reef community is the reef itself, so be careful not to include inhabitants that will prove harmful to the delicate corals. Following are a few recommended reef critters:
Tomato Clownfish – A reef favorite. Buy only one or either a pair. Provide anemone for fish.
Blue Chromis – Best in groups of 3-7. Hardy. They add color and motion to your tank.
Snowflake Eel – Less aggressive than other eels. Eats mostly crabs. Feed with a stick.
Coral Beauty – Small purple and orange angelfish. Best to have just one.
Pacific Blue Tang – Bright blue and yellow, eats algae from coral.
Sea Urchin – Mathaei species most recommended.
Shrimp – Cleaner Shrimp most recommended species.
You’ll also need some live tank cleaners like snails, crabs, and sea stars. Assortment packs are widely available.
If you adhere to the proper guidelines and maintain correct levels within your tank, you’ll have a source of unparalleled beauty and wonder, offering many hours of fascination.