Getting Started in Reefkeeping, Part 4

Water Motion

The last area that is crucial for successfully setting a reef tank long term is also one that is often overlooked - good strong water movement. Proper water movement is important for a number of reasons. First, considering that the ocean is the furthest thing possible from a stagnant pool it is logical that the organisms present on the reef are accustomed to an environment with strong water movement. As a result they have developed physiologically to make use of the water moving around them. This is especially true of the sessile invertebrates such as corals and clams that we keep in our aquariums. These organisms have developed physiologically to make use of the currents bringing them such things as food, oxygen and nutrients, as well as carrying away their waste products. This is why most corals grow perpendicular to the current. Several authors have reported that new growth of Acropora is often spindly relative to the growth of the old colony if the water movement around them is lowered. This has been the experience of many hobbyists; when low water velocity flows across stony coral colonies the growth is either slower or more spindly relative to the original growth pattern. However, if the flow is increased the corals may resume their original growth pattern and the speed of growth may also increase if all other factors remain the same. This increased flow not only increases the thickness of the new growth, but the previously spindly growth may thicken as well.

Another often-overlooked aspect of water movement is its effect on the fish's health. If you look at the labels of many fish foods you will find that one of the largest components is fat. This is an important component in nature as fat is quickly converted into energy. This is great for fish in the wild, as these fish are for the most part very active and require large amounts of energy. If however fish are placed in an environment where they don't have to fight the current the result could be the development of fatty deposits that result in a shortened lifespan. Therefore strong water movement may also contribute to the fish's health and longevity.

While getting good water movement is highly desirable the means for doing so is still a little difficult to achieve. The best means at present is to use power heads. However, they should not be pointed directly at the corals, as their force will shear off the tissue from the coral. Instead they should be directed so that their flow is against that from other powerheads. In this way the flow they produce may be more random as it is in the ocean. Additionally electronic devices such as wavemakers can be used to further enhance the randomness of the flow. There are many other ways to achieve this as well, but for the most part, using powerheads is a good way to initially provide good water movement.

Stocking Levels

The last aspect of starting a reef tank that is often not discussed is the number of fish and invertebrates can be maintained. In the old days the rule was one inch of fish per 10 gallons of water. However due to improvements in technology and a better understanding of biology and fish behavior in general, this rule is no longer valid. A tank established in the manner described above can biologically handle more of a fish and invertebrate load than was ever possible with tanks utilizing an undergravel filter. Actually this system is so efficient that the fish limit per tank is now due to behavioral limitations because of the aggressive nature of many of the fish we keep. Having said this, the rule for new hobbyists just starting out is to understock the tank. If more hobbyists heeded this advice the level of success would be much greater. The reason why you should understock a tank when starting out is simple: it provides a much greater margin for error. Despite good intentions and following the rules of the hobby, a new hobbyist will invariably make a mistake or two. In an understocked tank, these mistakes will be less likely to be fatal than they would if the tank is overstocked. Also, when a tank is overstocked there is a much greater likelihood of encountering the number one problem of reefkeepers: an algae bloom that overgrows the tank. For these reasons stock the tank as lightly as possible for the first year until you gain experience, which in this hobby is priceless.

Hopefully the information provided above illustrates that getting into the hobby is easy and the skills to be successful are actually quite simple. This hobby can be quite rewarding and provide a lifetime of enjoyment when done properly. So once again read as much as you can before getting started, plan well and be patient and your chances for success will be great.

Pictures related to this articles series can be found here.

Mike Paletta is the author of The New Marine Aquarium and Ultimate Marine Aquariums. He has been in the hobby for over 15 years and has written numerous articles for Aquarium Fish Magazine, Tropical Fish Hobbyist and Aquarium Frontiers.