Another alternative method has many names: the Monaco, Jaubert or sand plenum system. This type of aquarium setup was developed by Dr. Jean M. Jaubert and the most successful tank of this style is found at the Aquarium in Monaco. To establish a Jaubert system, one needs a large amount of sand. A small platform is created to sit directly on the bottom of the tank, much like an under gravel filter, but with very small pores, so sand does not sift down to the bottom. This creates an empty space, or stratum, of water. Above this, will be a thick layer (2-3”) of crushed coral and sand lies, covered by a screen to prevent burrowing animals and fish from penetrating it. On top of this, yet another layer of sand and coral lay, again 2-3” deep.

The premise is that the water slowly diffuses through the many layers of sand and empty space on the bottom and is filtered by the many bacteria living there. The top layer of sand is sifted and burrowed through, aerating the substrate which enables beneficial aerobic bacteria to live. The next layer is not touched by large animals, and the conditions become fairly anaerobic, giving way to another type of bacteria. These anaerobic bacteria consume nitrogenous end products (such as nitrates) and transform it into nitrogen gas, which then bubbles out of the tank. The draw for a tank such as this is the highly reduced need for water changes as complete filtration is performed here.

Unfortunately, the Jaubert system is not well suited to the home aquarium, because in order for there to be sufficient quantities of bacteria (both aerobic and anaerobic), roughly 80% of the bottom must be open. This tends to leave the display looking a bit sparse, and the long term results are not guaranteed. Additionally, since the top layer of sand and gravel must be aerobic, a large amount of animals must be purchased to accomplish this---no such requirements exist for the Berlin system.