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NNR System w/Jaubert Plenum

Utilizing Processed Eggshell Substrate

This is a Report on a Natural Nitrate Reduction System utilizing the Jaubert Plenum with an experimental Processed Eggshell Substrate.

I have completed a 6 month long test of the Jaubert Plenum using processed Eggshells as the substrate. No it's not a misprint I did say Eggshells.

I chose eggshells because they are FREE and I just love the word FREE, little did I realize the amount of eggshells required would be so phenomenal, and the process to prepare them for such use so much trouble.

My original theory was that the eggshells would require regular replacement and the calcium levels would remain constant. The tanks were designed such as to allow ready replacement for the consumed calcium. Such was not the case and the addition of kalkwasser was required as in a regular reef aquarium.

I had kept careful notes and planned on an elaborate dissertation about my discovery. However, after all is said and done, I can summarize the entire six month project into one sentence.

The Jaubert Plenum works and works well! No matter how shallow or deep the substrate is placed between and over the screens.

Previous to this experiment, I have used aragonite, puca shells (ground fine like sand), plain old river sand and tempered glass granules. Each substrate produced the same results. Nitrate FREE aquaria.

The only subtle little difference between all the aquaria, was whether I used live sand or dead sand on the top layer. I say subtle, because the only difference was the time element before denitrification began to occur. In all cases, there was only a 3 to 3-1/2 week difference between tanks started using dead sand and tanks started using a partial live sand top layer. Using live sand in the bottom layer indicated a detrimental effect and actually took longer to cycle than tanks using a dead sand center layer.

For you guru's out there that have always wondered how much substrate to use, I can finally give you an answer based on equal tests between equal aquariums, using all kinds of substrates. On aquariums that measure 20 inches or less in height, regardless of gallonage, I have found the ideal depth for the first layer to be 1-1/4 inches and for the top layer 1-3/4 inches. It is preferable to also have the center screen framed and supported to allow fines to filter through the screen without decreasing the depth of the first or bottom layer as some consumption of minerals from the substrate used is eminent.

For aquaria measuring 24 inches or under in height, but taller than 20 inches. First layer of substrate 1-1/2 inches, top layer 2 inches.

For aquaria measuring 30 inches or under in height, but taller than 24 inches. First layer of substrate 2 inches, top layer 2-3/4 inches.

However, do not be alarmed if your measurements are not equivalent to these. The identical test aquariums were operated with substrate layers of 3/4 inch total depth in the shallowest to 6 inches total substrate depth in the deepest. All tanks maintained zero nitrates after initial cycling throughout the entire 6 month test. Purposely elevating the nitrates in each tank proved that the Jaubert Plenum worked in each test tank. The only difference was the amount of time until the tank was back to zero nitrates. The substrate depths shown above gave the fastest recovery times throughout all 6 months of the test, whereas the extremes took sometimes up to a week longer, especially the shallow filled aquarium. The overfilled aquarium was sluggish, but always stayed within two days of the fastest aquaria.

After 5 months had passed, I began experimenting with removal of water from under the plenum. This was accomplished through an airline placed under each side of the aquarium plenum support structure. A slight benefit was noted by removing very small amounts of water, less than 1 pint per 10 gallons, from under the plenum but only in it's ability to rapidly remove the nitrates added to the aquaria. However, removing more than 1 quart per each 10 gallons was detrimental and the aquaria took longer to recover from nitrate addition. Using the drip method to remove less than 1 quart per week for each 10 gallons proved beneficial. But again, only in the recovery time of rapid introduction of nitrates. A reference tank was used during the plenum water drawing tests and I see an important item to consider here in my notes. The reference tank took considerably longer to recover after each heavy introduction of nitrates, than the time before. Unless more than a 2 week interval had passed before the next introduction of nitrates, then the times were back to normal on the first addition and increased thereafter.

***This ends the report on the Jaubert Plenum.***

Those curious about my eggshells substrate and test tank setup, please read on.

Let me start with the Eggshells and their preparation. An Eggshell consists of many components, the primary component of my concern was the calcium carbonate which is the major structure of the eggshell, however, included in the hard part of the eggshell is the mammary glands, which must be removed before use. As it takes over 900 dozen eggshells to produce enough calcium carbonate sand for a 75 gallon aquaria, I will omit the preparation process. If you would like to know how to do it using a common kitchen blender, e-mail me at (see /home/ page for current e-mail address) and I will be glad to let you know how. For ease of figuring 15 dozen fresh eggshells produce 1 quart of substrate after processing.

I used 4 twenty gallon tanks for the eggshell substrate test, each set up using exactly the same amount, type, weight and shapes of live rock, the same fish, inverts and equipment. The only difference between the tanks was the depths of substrate. Tank one started with both layers at 1/2 inch each and was later reduced to a total of 3/4 inches of substrate in an attempt to get the plenum to quit denitrifying. Tank four was started with both layers at 2 inches and increased to 3 inches in each layer, for the same reason. Tanks two and three were set up with 1-1/4 x 1-3/4 and 1-3/4 x 2-1/4 respectively. The plenum gap on all tanks was 1/2 inch and both screens were framed and supported.

At start up, each plenum was installed as mentioned above and the tanks filled with RO/DI water of .5 to .6 microsemens mixed with salt to 1.023sg. Each tank had two of the four lights turned on, on a 12 hour cycle. No protein skimmers were connected at this time. Tank one was cycled without any additional inhabitants (this could be done because of the organic impurities that remain in the eggshells even after processing). Tank two was cycled using only 2 garden peas and 1 piece of boiled shrimp the size of the two peas, squished. Tank three was cycled using a single damsel and Tank four was cycled using 4 damsels.

The tanks cycled in the same order, Tank one finished cycling (ammonia 0, nitrites 0.25, nitrates 40) in exactly 30 days. Tank two finished on day #36 (nitrates 45). Tank three did not complete it's cycle till day 45 (nitrates 40) and Tank four did not finish till day 51 (nitrates 60) and one fish was lost on day 46.

The water was completely drained, from the top, to the level of the substrate, not below, and refilled with RO/DI water and salt 1.023sg. The fish were separated, one into each tank and 40 lbs of cured live rock from of equivalent sizes and weights from the same holding tank were added. The protein skimmers were turned on and balanced and all four lights were now activated and the timers set for actinic on 13 hours, 50/50s 12 hours. Three days later I began feeding the single fish in each tank a single shrimp pellet each.

After two weeks had elapsed, tests showed that nitrate levels in all tanks were up to about but just under 20ppm. Each tank received a 50% water change, thereafter, for the remainder of the 6 months, only 1 gallon per week was removed and replaced from the tanks of saltwater.

I waited one more week, did the water change, removed the damsels and added one animal per day, except Wednesdays and Sundays, until the aquariums were equally stocked with my start-up lineup of animals, this took place over a period of 23 days. This is when I started counting down my 6 months, after the tanks were stocked.

Feeding was increased to four shrimp pellets and 1 gram of marine flake food for the remainder of the test, with only the addition of 10 adult brine shrimp per week per tank.

As mentioned above, the results of the test were not as expected. Calcium was not precipitated into the water after the first month as hoped. The addition of more eggshells were not required except as I purposely increased tank #4s and reduced tank #1s substrate levels. So the purpose of my test was in vain. Kalkwasser, or actually Ball pickling lime was used only in the top up water to replace evaporated water. Coralife Salt was used throughout the test, it has an initial reading of 450Ca. the tanks stayed at 400 Ca throughout the test with the addition of kalkwasser.

The results of the nitrate tests presented above indicate to me that the actual levels of substrate used were not critical to overall nitrate reduction in the aquarium. Other deeper tanks were set-up only for the purpose of finding a close to ideal depth for the substrate. Those tanks were adjusted starting from one inch all the way up to 6 inches also, but with no reference to go by other than time.

Needless to say, 6 months is not a long time to conduct a test, but since my initial theory was all shot to heck, and I found that the prominent substrate depth already known in the industry was accurate. I then balanced all the aquaria to this nominal depth with only a 1/4 inch difference between the tanks, so that I could test the effects of drawing water from under the plenums. The results of which are also mentioned above.

If you are a diehard, who stuck with my boredom this far, thank you! I might add, that during this test, I was also fooling around with various substrates and live sand more commonly associated with aquaria. My summation is that using live sand in the lower level of substrate is a waste of money and actually lengthens the time the tank cycles and reduces its denitrification capabilities. Using the many different dead sand types as the lower layer made no appreciable good or bad effect on the systems. The use of some live sand on the top layer speeded up the process and complete denitrification occurred much faster, like 2 months faster in the tank that used only live sand on the top layer.

The four aquariums will remain intact, for the time being anyhow, but the individual system components have been dismantled and returned to the store for resale. Only one sump and protein skimmer will be used, with Poly-Filters of course, to maintain the aquaria and animals.

Not all tests conclude with a positive or new feature, sorry guys.

Respectfully submitted,

Gary V. Deutschmann, Sr.

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