Bob replies...

Dear Adrian,

Thanks for your letter. I was once 12 years old and at that time had three years of keeping a freshwater aquarium. Of course that was over fifty years ago and have since learned the marine side of the hobby can be much more complex, especially when it includes invertebrates. With this much experience behind me I can understand your desire to keep marines, however, can also see some 'bumps in the road' with your proposed setup.

When it comes to equipment, two small internal filters utilizing sponge material for filtering water may or may not be necessary. If the sponge material is going to be used as a mechanical filter and will be removed and hand washed frequently, it should suffice for that purpose. Yet, if the sponge material is to provide biological filtration, it may clog rather easily and require cleaning in seawater so as to maintain the health of the bacteria. Actually, an additional biological filter will not be needed, as the plenum sandbed would provide all that is necessary.

The use of a protein skimmer is a very good idea as it not only removes some nutrients from the water, but also oxygenates it helping to provide a healthier environment for the animals in the tank. You mention the use of a plenum, yet note only the use of a half-inch of coral sand. Plenum sandbeds, i.e., the bed of sand above the plenum, are usually about four inches deep using a sand grain size of about 2 to 4 mm. The reason for that depth is that most of it will contain a very small amount of oxygen, or what has been termed an 'anoxic state' in our writings. That provides an area where the most efficient nitrate reducing microbes live. Having more microbes that function more efficiently than microbes that are not as efficient at this task helps to keep any closed system in a more balanced or healthier condition. Sand grain size is also important as diffusion of oxygen, other elements, compounds/nutrients is downward. Years of research have shown the size recommended with a four-inch bed works the best.

Should you not want such a deep bed, e.g., about five inches (Plenum grid and sand), I advise using not more than about two inches of sand directly on the aquarium bottom. That way, areas in the sand having no dissolved oxygen (below about one-inch) would be quite limited to anaerobic conditions. Just in case that is not understood, anaerobic bacteria as defined in our writings only reduce nitrate to ammonium, no further. Therefore another nitrogen compound, ammonium, is generated in those anaerobic areas and which is the primary algae nutrient. So reducing anaerobic areas in the aquarium make sense unless green is a favorite color.

As for fluorescent tubes, there are many to chose from. Some are better used in the home as general lighting and others are more specific as to where they can be used, such as over freshwater or marine aquariums. There are some key words that are helpful when selecting them. The first is 'spectrum.' It is defined by Webster's Dictionary as a series of colors formed when a beam of white light is dispersed (as by passing through a prism) so the waves of light are arranged in order of their wavelength from red continuing through orange, yellow, green, blue, indigo, and violet.

The Sun, a star located at the center of our solar system emits a broad "spectrum" of energy waves, some of which we can see and some which the human eye can not. The light the human eye sees is known as the "Visual Spectrum" and is only a small portion of the total electromagnetic spectrum discharged by the Sun.

When we see a rainbow we are witnessing a breakdown of the colors that comprise the visual portion of the spectrum, e.g., violet, indigo, blue, green, yellow, and red. The violet/indigo/blue portion of this "visible" light begins at a wavelength of 400 nanometers. The visible colors then change to green at about 475 nanometers, then to yellow at about 580 nanometers, which is the brightest portion of the visual spectrum. At 625 nanometers yellow changes to red, which continues to be visible until it reaches about 700 nanometers. Beyond this range, the spectrum consists of infrared wavelengths and is invisible to the human eye. Below the 400 nanometer range the spectrum is also invisible to our eye and it's this portion of the spectrum that contains cosmic, gamma, x-rays and ultra-violet wavelengths. The blue and red wavelengths of the visible spectrum are perceived by the human eye as the darkest areas of this light source.

If we were to engineer a lamp to give off a certain color, e.g., yellow, it would be brighter than any of the other visible colors given the same amount of energy. Therefore it is a lot less expensive to light places such as parking lots, ball fields, and streets with "yellow" light. Yet, lamps such as these have no value for photosynthetic invertebrate as they lack the spectrum, mainly blue, needed to trigger photosynthesis.

Even though spectrum is important, it can further be defined with the word 'Kelvin.' When a piece of metal is heated its color changes as it gets hotter. The progression of color, matched to its temperature (measured in Kelvin's), can be plotted to further define "color." If there is anything about this subject matter that should be remembered is that lamps emitting a color temperature of less than 5500 Kelvin are not beneficial for reef aquariums. They are simply too low in the blue wavelength. Actually, 5500 Kelvin is a noon time temperature and should be considered the minimum color temperature for any lamp used to light reef aquariums. Higher color temperatures contain higher levels of blue light.

When it comes to fluorescent lamps for use over a reef system, attention to their spectrum and Kelvin rating is important. If at all possible select a lamp that notes its visible spectrum range, sometimes found as a graph on the side of the lamp container, as having more blue light than yellow or red. Also, if possible, select something near the 10K range. Unfortunately some lamps for our purpose are only advertised as multi-spectrum, wide-spectrum, full-spectrum, broad-spectrum, etc. If so, choose those that say full-spectrum.

I doubt very much whether two regular wattage lamps, probably 24W each, will suffice for photosynthetic gorgonian and Green Star Polyps. Button Polyps may be okay. They definitely would not suffice for a Ritteri anemone (Heteractis magnifica). Yet, mushrooms, feather dusters, and Bubble Corals would do well. Making a choice between invertebrate requiring a lot of light or those that do well under low to medium light appears to be a decision that needs to made. If increasing lighting intensity is possible, you can stock the more light loving animals such as the gorgonians, yet not the anemone as it should have a much larger aquarium. If not, stay with Bubble Corals (Plerogyra sinuosa), Mushrooms, and some other medium light animals such as Torch Coral (Caulastrea furcata) or Brain Coral (Trachyphyllia geofroyi), Open Meat or Sea Button (Cynarina lacrymalis) or Euphyllia. There are three species of interest: E. ancora commonly called Hammer or Anchor Coral; E. glabrescens called Torch Coral; and, E. divisa called Frogspawn, Wall Coral, or Zig-Zag.

As for the Mandarin, that would be something you only want to add to the tank once it has fully matured as they need a constant supply of live crustaceans, such as copepods. Otherwise, they will starve to death. And I doubt your small system will be able to supply enough of its natural food supply.

When it comes to Feather Dusters, they are often found in the wild buried in sand/mud. Their tubes are constructed of sand, detritus, mucus, and other bits of sediment. It is better to locate these worms near the bottom of the aquarium where this material is more plentiful. The fact that particulate matter is higher near the bottom of the aquarium and they are not photosynthetic, are other good reasons to place them near the bottom of the aquarium.

They use their slime-coated filaments/tentacles or "feathers" as some call it, for respiration and to collect suspended particulate matter/plankton. The collected matter is then drawn towards the mouth area at the center of the tentacle ring. Solutions containing phytoplankton or zooplankton (rotifers) are recommended. These feeding solutions should be applied near and under the crown of feathers so it can normally be drawn up and to the beating cilia on the feathers. It should be noted that these tiny hair-like extensions generate the current that draws the food supply into the feather-like head of the animal. Simply dispensing the feeding solution above the animal may cause the animal to retract with most of the feeding solution going to waste/elsewhere.

Feather dusters may lose their crown of "feathers" for many reasons, some being; poor water quality and/or being disturbed too often. This does not mean they are dead as most will grow their feathers back in a month or so. Always wait a couple of months and if no reappearance occurs, feel the tube for the worm inside. If there is some movement inside the tube, put it back and be patient for another month.

When it comes to keeping any of the ornamental type worms, predators like triggerfish, wrasses, angelfish, most shrimp, and the arrow crab will not make suitable tankmates. Unless you intend to hand feed, they should not be placed in a new system. Give the tank about six months it mature so that some detritus is present in the sandbed. Then stir the sand so as to suspend some of it so the animals can draw it in.

When it comes to urchins, they do require a lot of algae to stay healthy. They also strip coralline algae, which is sort after by many reef keepers. It's your choice, however, something I'd give more thought to. I would also think twice about having an Arrow Crab in the same small tank as four Cleaner Shrimps. Anything with a claw can be dangerous, especially to something tasty such as shrimp/feather dusters. When the shrimp molt they are totally defenseless and can't run and hide. A perfect time for the crab to get them.

When it comes to water quality, salinity, pH, alkalinity, and calcium are the most important to maintain. Salinity should be maintained in the range of 1.025, pH near natural seawater level of 8.1 to 8.2, alkalinity in the range of 10 - 12 dKH, and calcium near 400 mg/l. To easily care for pH, alkalinity and calcium with one additive product, I recommend using any of the two-part calcium and buffering additives on the market. Salinity is easily checked with any of the plastic hydrometers on the market. I would also test nitrate occasionally, and as for test kits, Aquarium Systems Fastest Kits would suffice for measuring all these parameters as would many other brands.

As for feeding, if you upgrade the lighting and decide on keeping the anemone, it prefers its base attached to rock in open water where there is good water flow and intense light to stimulate its symbiotic zooxanthellae. As for feeding, small pieces of silversides, shrimp, krill, fresh fish flesh, and/or whole fishes fed once to three times a week should suffice. Place the food morsel on the tentacles or near the central orifice.

I highly recommend reading up on any animals before placing them in you system. Many have requirements quite opposite from others and placing them in the wrong environment could lead to their loss. In fact, it could lead to the loss of the whole system, which may turn you away from this wonderfully educational hobby. There are many magazines where advice from experts are available and websites where a wide range of topics are discussed. Search them out and be sure about an animal's need before purchasing it.

Hope this helps and don't hesitate to ask more questions,

Bob Goemans