I personally would never use a Jaubert System (or Plenum System). To me, they seem like a ticking time bomb. Jaubert Systems require very light stocking, overstep that capacity by even a little and BOOM! All your fish down the drain.
The idea behind them is indeed to complete the nitrogen cycle. They were controversial even in the olden days (back when undergravel filters were the best filter there was). Basically, a true Jaubert System has no machinery except for a protein skimmer (a gamble at best) and all filtration is accomplished by live rock and algal fronds. Then, the anaerobic plenum converts nitrates into nitrogen, but this situation has some major flaws, for instance, how the hell do nitrates get down under a crate to be processed? But anyways, it did actually reduce the frequency of water changes, if by only a little.
In conclusion:
The Cons of a Jaubert System:
-light stocking only
-coarse gravel only
-no powerheads, otherwise the anaerobes might be upset
-plenums are ugly as sin
The Pros of a Jaubert System:
-potentially reduced frequency of water changes
-a cheap method of setting up a marine tank
If I were you, I would stick to a good ol' Berlin/Sand Bed system. They were and still are the best.
Berlin/Leng Sy systems are showing major promise as well.
-Lynden
