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By Gary V. Deutschmann, Sr.
Very little information has been published or made available about Natural Nitrate Reduction (NNR), until 4 years ago. At that time, Dr. Jean Jaubert installed a screen within his system substrate, separating it into layers. This was to prevent burrowing animals from digging too deep in his substrate, upsetting the balance of the NNR going on in the aquarium. Dr. Jaubert then published a paper (Captive Seawater Fishes), explaining enough details for the first time, for others to reliably reproduce a Natural Nitrate Reduction system of this type.
Although it is touted by many authors and columnists as "the Next Major Improvement in Reef Keeping", Natural Nitrate Reduction is not new. In fact, it was discovered, perfected, and promoted more than 30 years ago, by Lee Chin Eng as part of a "Natural System" for keeping marine fishes with living corals and invertebrates.
One must realize that 30 years ago, very little was known about reef animals. Nothing was written or published on their care, and suitable equipment was literally unavailable. However, nothing was impossible to the avid aquarists who strove to achieve their goal, owning a piece of the coral reef in their home.
Lee Chin Eng was one of those early pioneers who kept searching for a way, until he found it. Lee knew his system worked. In fact, every "Natural System" that he assembled was quite successful. Unfortunately, Lee was not able to articulate the key techniques that would allow others to duplicate his success. Only through experience, Lee had developed little assembly techniques, and an overall system that worked well. When others tried to copy the system, they must have modified details that they were unaware of, but that turned out be essential. More than likely because, at that time, the key elements to his discovery were not yet defined. Processes and terminology that are common to us today, were not yet developed, much less understood.
After much correspondence, and guided mainly by numerous old photographs supplied by Dr. Herbert R. Axelrod, I was able to duplicate Lee Chin Eng's "Natural System" with outstanding success, back in the early '70s. I also had the opportunity to speak with others who tried the "Natural System" and failed miserably. My best source of information became speaking to those who failed. Most were very precise in explaining how they set up their system, and soon, a common difference between the working systems and non-working systems was found.
The first, and most obvious, problem to appear in systems that were going to fail, was large masses of hair algae appearing in the aquaria. With careful comparison of the construction techniques, one common factor became clear in all of the systems that failed. When placing the first layer of stone, these aquarists did not place rows of small stones supporting the larger flat plate stones. Today we refer to this space as the "Dead Space" or "Plenum" under the substrate. Other systems that failed, that did have this space, failed to duplicate Lee's system elsewhere, or used too many large flat plates over the substrate, which caused other problems.
In a properly set-up "Natural System" a "Dead Space" was one of the key elements of Lee's design, followed by a thick layer of coral sand over the flat plates. It was then natural for Lee to place medium to small pieces of live rock, covering the entire sand substrate and eliminating any digging problems by burrowing animals. This was then followed by larger encrusted live rock that nearly filled the aquarium to the top near the back.
The "Natural Method" of Lee Chin Eng, was not a cure-all to reef aquarium ownership. At that time, water changes were considered a detriment rather than a benefit, and cured water was relished like gold! However, the "Natural System" was a major step in the right direction, and held nitrates well below 10mg/l. Tank materials were still a large problem, and plastic components were just appearing on the horizon.
With increasing knowledge and a better understanding of how Lee Chin Eng's "Natural System" functioned, many changes were made to the system. By the early '80s, the costly live rock under the substrate was replaced with old style UGF filter plates. Calcareous gravel replaced the lower part of the substrate, with a thin layer of live sand over that, followed by much live rock. Still, total nitrate reduction was not achieved. Then a fad hit the reef keeping hobby in the US, and most aquarists eliminated substrate altogether from their systems. Further experimentation with Lee Chin Eng's "Natural System" fell by the wayside for a time.
As higher nitrates were experienced in tanks that contained no substrate, eventually aquarists began to once again experiment with silica sands and calcareous gravels. As in the improperly set-up "Natural System", the hair algae problems and incomplete nitrate reduction became commonplace. Then a few aquarists started using old UGF plates, creating a dead space under the substrate. This partially eliminated the algae problem, but nitrates were still hovering between 6 and 8 mg/l in most systems. Also, as burrowing or stirring animals became more readily available, in systems containing well spaced live rock base, the substrate could easily become disturbed, and sudden rises in nitrates would occur.
Apparently, Dr. Jean Jaubert was one of these aquarists who set out to find a cure. In the early '90s Dr. Jaubert had replaced the UGF plate with a lighting eggcrate covered with a fine mesh nylon screen, which he later improved by using fiberglass screening covered by nylon mesh. Soon thereafter he placed a second lighting eggcrate covered with fiberglass screen to prevent the burrowing animals from digging too deep into the substrate. After he had perfected his method, he wrote an article, "Captive Seawater Fishes", which explained his new system. (I believe this also appeared in one of Stephen Spotte's recent books.)
I believe Dr. Jean Jaubert should be given the credit for developing the first NNR system that totally reduces nitrates. Lab tests on several systems utilizing the "Jaubert Plenum" with various different substrates found the nitrate level to remain below .01mg/l continually. However, the credit for the title "Natural Nitrate Reduction (NNR)" may go to Bob Goemans Ph.D.. Although I had heard it used years earlier, he is the first person to use it in print. Lastly, the credit for the overall NNR System or "Natural System" should by all rights go to the person who discovered, and for many years, promoted it's use: Lee Chin Eng.
I will also note that systems utilizing the "Jaubert Plenum" are quite robust. Systems grossly overloaded with large live rock bases, even after years of use, have never shown any indication that a build-up of hydrogen sulfide has ever occurred in the substrate. So don't be afraid to try the "Jaubert Plenum" in your own reef aquaria, it works and works well, and only takes about three months to become fully active.
Written exclusively for RTO Features by Gary V. Deutschmann, Sr.
HTML by RTO. Copyright 1996.
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