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Marine Reef Aquariums Made Easy
By Tony Griffitts
At Aquaworld Aquarium when you enter the front door you are greeted by a 10 gallon flat back hexagon aquarium. Many customers have commented that they have been told that a small reef aquarium is very difficult to maintain. I usually respond by saying that that is not true, and that our 10 gallon reef aquarium is the lowest maintenance aquarium in the store. How is that possible? When you add good lighting, the right supplements, once a week freshwater top offs, and the right animals, the aquarium almost takes care of itself.
Ten gallon Flat Back Hex aquarium made byTRUVU at the front of Aquaworld. The light is a 28 watt 6700K power compact fluorescent retro mounted in the canopy. The filter is a Marineland™ Penguin® Bio-Wheel Mini.
To start off the aquarium right you must start with the proper lighting. Most aquarium kits sold today have inadequate lighting for a reef. Most aquariums are sold with incandescent or standard fluorescent fixtures, which are in most cases way underpowered for a reef. In most cases you will need a third party lighting system. Meaning you will have to get the light fixture from a source other than the aquarium manufacturer.
Today we now have Power Compact Fluorescent lighting systems that have made lighting and maintaining a reef aquarium much more economical. Energy Savers Unlimited (Coralife®) and Catalina Aquarium makes Compact Fluorescent lighting systems that are very good for reef aquariums that are 24 inches (60 cm) or less in depth. In most cases one row of lights is good enough for aquariums 12 inches (30cm) or less in width. If your aquarium is more than 12 inches (30 cm) wide you should add another row. If your aquarium is 24 inches (60cm) wide you may want to consider three rows, but two rows will be adequate for most corals.
The best bulbs for reef are 10000K bulbs. You can use them exclusively or with other spectrum bulbs, like 6700K or Actinic (Blue Light). The 10000K bulb has the blue light spectrum incorporated so supplementation with Actinic is not necessary. Actinic blue light bulbs came into the reef hobby back in the 1980's when most commercially available bulbs lacked the blue light spectrum. It was/is used as a supplemental bulb and not as a primary source of light.
So why all this talk about lighting? Most corals (both soft and stony) need the light for the symbiotic algae that lives inside the tissue called Zooxanthellae. This algae provides food for the corals, and in many cases it is the sole food source. Many types of zooxanthellae have evolved to use the blue light (Actinic) to grow and reproduce, therefore it is an important light spectrum for your reef aquarium. If you try to use the actinic light exclusively, your aquarium will look like the ocean's coral reef at about 90 feet (30 m) or more of depth, in other words, very dark. Many red fish at that depth look black. Blue light penetrates the water the furthest, which may explain why zooxanthellae have adapted to that spectrum.
Most aquariums 20 gallons (80 l) and under can be upgraded to compact fluorescent lights for as low as $80 to $120 for a single fixture that includes the light bulb.
Pictured are Coralife®'s Power Compact lights in a 24" Aluminum hood and a retro fit kit for mounting into a canopy. Coralife also makes double bulb fixtures that are very good for most mini reefs.
Filtration is the next step to designing the aquarium for reef. A good hang on the tank/back filter like the Marineland™ (Aquaria, Inc.) Bio-Wheel filters. I recommend you choose one of the models that will turn over the aquarium at least 10 times an hour. I use the Penguin® Bio-Wheel Mini for our 10 gallon aquarium.
Protein skimmers in my opinion are optional. We have three reef display aquariums at Aquaworld that do not use protein skimmers. If you have a protein/scum build up on top of the water in the aquarium, you can turn off the power to the filter, and take a paper towel sheet and lay it on top of the water, and then pull it off. This will wick up the proteins and remove them from the aquarium. Once you have removed all the proteins power the filter back on.
You may need a heater for the aquarium. Whether or not you need one depends on how warm your aquarium will stay without a heater. If you can maintain at least 72° F (22° C) you can usually get by without one. Lighting systems will transfer some heat to the water, so even though the room temperature is only 70° F (21° C) your aquarium will usually be several degrees warmer. Make sure you invest in a thermometer.
You will need a hydrometer to measure for salt level content. Marineland™ makes a new re-designed hydrometer that I recommend for Nano/Mini reefs. We try to maintain a specific gravity (salinity) of 1.023 to 1.024 in our aquariums. Instant Ocean® and Reef Crystals® are our preferred salts. You should first add water and salt to your aquarium and let it mix overnight with the power filter running. The next morning test the salinity. Add more salt to raise the salinity if necessary, or take out some water and add fresh water to lower the salinity. Let it mix another hour and test again. Once the salinity is at the desired level you can then start adding livestock.
There are 3 trace elements you should add on a regular basis. Calcium, Strontium, and Iodine are the trace elements we add at least once a week to our reef tanks. Calcium and Strontium are added for the stony corals, as they will strip these trace elements out of the water for there stony skeleton, and Iodine is needed for shrimps and crabs, so they can molt properly.
The best substrate for the reef aquarium is very fine aragonite (coral) sand at a depth of 2 to 3 inches (7.5cm). A 50-pound bag covers 325 square inches at about 3 inches or 10 pounds will cover 65 square inches. A typical 20-gallon would require about 45 pounds, and a typical 10 gallon would require 30 pounds. Why the fine aragonite sand? The number one reason is, once microorganisms colonize the sand it will start reducing nitrate (NO3). The lower depth of the sand bed houses anaerobic bacteria that use the oxygen atom on the nitrate molecule to breathe. The sand will slowly be turned over by small organisms that live in the sand bed. This will allow the water to slowly be exchanged in the lower sand bed, allowing an anaerobic condition to exist. Large forms of gravel will allow to quick of a water change over for an anaerobic condition to take place. It can be done, but it would require an extremely thick bed.
Live Rock and/or Live Sand and/or Bio-Spira from Marineland should be added to the aquarium after the salinity has been set. This will help seed the aquarium with beneficial bacteria that will break down ammonia and nitrite.
The base Live Rock should be in contact with the bottom of the aquarium. Once the base Live Rock is in contact with the bottom you can then pack your sand around the rock. This is done to help prevent any animals from undermining the rock and then creating all the rock to shift and possibly tumble down, risking the tank breaking or getting scratched. Live Sand should be added on top of the dry sand. You want the beneficial bacteria in the live sand to be in contact with the water column.
Once your aquarium is set up it is normal to go through algae blooms. The first algae that shows up is a brown algae, then usually followed by green hairy algae. Algae can be controlled by adding 4 Astria (Florida Turbo) snails per 10 gallons.
I prefer to cycle the reef tank with crabs and shrimp, rather than fish. They tend to be less of a bio-load on the aquarium and seem to tolerate ammonia and nitrite better than fish.
Mini (Nano) reef tanks are a very good way to get your hands wet in the reef hobby. Contrary to what many people have said, small reef tanks are very easy to keep. Many of the animals are very hardy, and will live for many years.
Published - 2004