Continued from page 2If the goal is to make aquarium keeping simpler, then a reduction in skimming and the addition of photosynthesis may be a better approach. Moderate foam fractionating (key word is moderate) in combination with RDP will allow the positive effects of each to more than balance out any negatives.
In an attempt to more closely duplicate the natural aquatic ecosystem (remember this is the key ingredient in most success stories), live rock and live sand is also part of the RDP concept. The addition of a proper substrate bottom, which was not part of the original US interpatation of the "Berlin" concept contributes to the filtration process and helps support the natural levels of calcium, strontium, and other beneficial trace elements found in sea water. Just think how much sand is on the bottom of the ocean and the amount of life it contains. By not including this in your aquaria, you are missing a very large portion of the biome.
Healthy live sand contains microorganisms growing on and in it. The use of this natural substrate also provides habitat for many fish and invertebrate species that were not able to be kept in the past, but now increases your selection of ornamental Aquatic WildLife which can be added.
Live Rock (the backbone of coral reefs) has a variety of algae and microorganisms growing on and in it. Live rock is much like the live sand in that also plays a key role in the filtration process and provides habitat. The addition of live rock, however, does not have to be limited to "reef" aquaria. Corals, plants, spiral gilled tube worms, and other life forms found on "decorator" live rock that would become expensive forage for the fish species normally kept in "fish only" tanks do not have to be added.
Live rocks encrusted with rainbow colored coralline algae can, however, replace the bleached coral skeletons normally used as aquascape with these fish species. This coralline rock will provide the same esthetic value as bleached coral and at the same time contribute nitrifying and denitrifying bacteria and other microorganisms.
Note the word healthy used to describe the live rock and live sand. When "live" rock and "live" sand is packed and shipped from some exotic South Pacific island extended shipping times are required before it arrives in the USA. This time out-of-water (or box time) takes its toll on most of the organisms that live on and in the rock and sand. The once "healthy" live rock and live sand arrives essentially died.
Cultured live rock and sand purchased from mariculture facilities located within the continental US or harvested rock and sand that has been maintained in an ecosystem (closer to the market) for a period of time long enough to allow it to recover from the stress of shipping, offers a number of advantages. If ocean fresh (read live) rock and sand is used to establish an aquaria it will not have to go through the "normal" cycle period before all the animals you desire can be added. A properly aquascaped RDP concept aquarium can be setup from an empty tank to a fully loaded system in less than 48 hours.
Replicating natural light is also a critical key element to the long term survival and well being of corals and other invertebrates especially those that are photosynthetic (use light as food). Selecting the proper light intensity (watts), Kelvin temperature, (color) and style of bulbs (Power compact florescent, metal halide, VHO & HO florescent, etc. or even a combination of these) best suited for the type of aquatic biome you want to duplicate can be a time consuming and confusing task.
There is as many opinions as to what type of artificial light source is correct as there are styles of bulbs. Since this article is on RDP and not an in-depth article on lighting, I will leave choice of lighting up to the individual who sets up the aquarium.
However, it has been suggested that replicating the natural lunar phases may induces sexual reproduction and a more natural behavior in most aquatic life, including stony corals.
This simulation includes the time the lunar light comes on, how long it stays on, the increase and decrease in intensity as the moon goes through its cycle from new to full, etc. It may also be beneficial to the behavior and well being of some aquatic life to increase and decrease the daylight Photo period and intensity in a more realistic simulation of natural lighting variations, including sunrise, sunset, high noon, and length of daylight (winter through summer) etc. It is for these reasons that the RDP concept begin outlined suggests that a preprogrammed micro-processor that automatically controls all of these functions be part of the integrated system.
Water movement is an meaningful part of the aquatic world, effecting respiration, feeding, growth and reproduction of corals, fish, calms, plants and other aquatic life. The RDP concept also duplicates the three main types of natural water movement, wave action, turbulence and laminar flow.
The natural back and forth action caused by waves normally missing in aquariums does more than add motion and interest. In nature, it plays a key role exposing more of the surface area of the flexible corals to sunlight, increasing feeding efficiency and the exchange of metabolites and gases within the water. Waves also disturb and mix surface layers and create ripples. These ripples magnify the light forming "glitter lines" or bands of light brighter than the normal ambient light. This moderate strobe effect adds the appearance of motion, depth and interest to the aquascape and at the same time provides the beneficial effects of pulsed energy to the animals.
Turbulence is caused when the natural wave action (surge) meets the more Laminar or constant one direction flow produced from the spray bar. Replicating the three main types of water movement found on a coral reef provides different biomes or aquatic zones that many organisms evolved in.
Meeting the Nutritional requirements of the variety of captive animals can be a full time job. Herbivores, carnivores, omnivores, planktivoures, and detritivores are classifications of Aquatic WildLife based on what they eat. However, they all have one thing in common. In nature they all forage, graze or filter feed continuously. The easiest way to provide the proper nutrition on a continues basis is to replicate what nature does.
By introducing the smaller life forms (i.e. copepods, mysid shrimp, etc.) and providing natural habitat (live rock and sand) for these living vitamin capsules you provide natural forage for the carnivores and omnivores that they can seek out and eat. However, being efficient hunters they can deplete the natural population in an enclosed system rather quickly. In the RDP concept aquaria a refuge area is built into the main tank design as a safe harbor for delicate organisms to live and reproduce away from predators. It shares the same water as the main tank, allowing some of the organisms to enter the main tank as natural live food.
The larval stages of these copepods, mysid shrimp, and other microorganisms that live and reproduce in the refugia enter the main aquaria as plankton, thus feeding the filter feeders and planktivoures. The herbivores and detritiovrs are primarily introduced to an aquaria as natural maintenance engineers and will feed themselves. The incorporation of a properly designed refugia can greatly reduces the need to manually feed the aquarium.
The refugia also aids in the filtration process, replicating the lagoons and estuaries in nature. The slower moving water (in comparison to the rest of the aquarium) allows solids to settle out (natural mechanical filtration) so bacteria and detritiovrs can break this down. The refugia can also serve as habitat for ornamental organisms (i.e. coral banded shrimp, etc.) that might become food for predators kept in the main aquarium.
This refuge is incorporated in such a manner so individuals who wish can easily view the inhabitants through one end of the aquarium and/or through the window from the front of the aquarium. This design does not distract from the esthetic design of the over all aquaria and puts the refugia out where it can be enjoyed.
Conclusion
Why should the esthetic beauty of a captive marine environment be limited to a select group of skilled and dedicated people? It is the allure of the animals and not an interest in gadgets or the desire to "tinker" that first draws most people into the hobby.
Designed with the non-aquarist in mind, the RDP system allows the average person to enjoy the educational benefits and soothing beauty of the aquatic world within their own home or work environment.
Televisions, stereos, computers, etc. are no longer purchased as individual components to be pieced together by the average consumer, but rather are available as a complete package that was designed by professionals to perform successfully and as simply as possible. So, why not aquariums? The RDP concept is a well designed, integrated aquarium system that models natures ecosystem.
John C. Walch
July 19, 1997
Las Vegas, NV
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