Setting up a Jumbert system

[Conky]

"As for rocks in Jaubert systems, the ORIGINAL Jaubert system only has minimal rocks. What you mentioned are modified Jaubert systems, which Sprung explained in detail, will cause the system to fail over a long period of time."

Why? I'm very curious....guess I better get the book. Our 4000 gallon reef is such a "modified Jaubert" system and has been operating for over 10 (maybe that's not a "long" time) years without any major issues. NO3 < 4 mg/L, PO4 <0.03 mg/L, Ca and Alk maintained at reasonable levels with kalkwasser additions. Why is it destined to fail? It's dominated by soft corals (mostly Sinularia, Capnella (maybe), Sarcophyton, Lobophytum, Zoanthids, Corallimorphs), but has two laminar Hydnophora that are well over 2 ft across as well as a couple of Acropora and some larger-polyped species (Platygyra, Physogyra, Plerogyra, Scolymia, Turbinaria, Euphyllia, Caulastrea, etc.)

How long is a "long" period of time, I wonder?

Not mocking you...I promise. But that's a big statement from someone who has never examined quantitative data. Lots of people have blame lots of "techniques" for tank crashes over the years. In reality, I think we're all just rolling the dice...

Why do i feel like I've just DOOMED myself for a catastrophe? Gotta go find some wood to knock on...

 

[goodreef]

From what I gather from the book, it is important in the Jaubert systems to have water diffusion in the sand beds. If too much rocks are on the sandbed, water hitting the rocks will push detrius into the sand bed, thus greatly reducing the space between the grains of sand. Similar to "clamping" effects on sand bed. Once water diffusion in the sand bed drops, hydrogen sulphate forms, and things goes down from there!!

But if the rocks are minimal, or if they are lifted off the sand bed, the sand bed will remain relatively free from "blockages" and water diffusion and its filtration effects will be optimised.

 

[goodreef]

To quote Delbeek & Sprung in The Reef Aquarium, pg 343-344

"In a properly established Jaubert system aquarium there is much less rock, leaving wide expanses of the bottom uncovered. The reason for this is twofold. First, since the biological filtration occurs within the gravel bed, the live rock is not needed for biological filtration. One can set up a Jaubert system with no rock at all. Its purpose is just for decoration and the introduction of biodiversity. The second reason for the paucity of rock is that the surface of the gravel bed should be left uncovered as much as possible. This allows unrestricted exchange of oxygen and other dissolved substances, and minimizes advection of detritus into the substrata."