This age-old question comes out often among aquarists, and the answer will surprise you.
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But first of all let’s go over some definitions in order to better understand what we’re talking about. We’ll start with the one we all should know already, which is the Berlin.
The Berlin Method in short
At the end of the seventies, the Berlin Aquarium Society started a new kind of experimentation on marine aquariums, thanks to the aquarist and writer Peter Wilkens. A trial protracted until the beginning of the eighties, and today it goes on all over the world. This new method, named Berlin Method, considers the marine aquarium as a balanced ecosystem (or more like pseudo-balanced, because its environment is way smaller than the sea) to be studied in its complexity and not considered a set of disconnected parts, in antithesis with what was the main direction at time.
The Berlin Method has its own rules:
- use of 1 kg of living rocks for every 5 liters of water;
- intense lighting;
- strong movement;
- use of the skimmer;
- reintegration of calcium and carbonates;
- use of active carbon.
The DSB in short
Starting from the same biological basis of the Berlin Method, the question came up if the work of the bacterial substrate could be performed by something besides the usual bulky living rocks. The transformation of nitrate into oxygen and nitrogen primarily happens in anoxic zones, which are environments with a low level of oxygen; it’s the most critical part. So new experiments were done, with a deep sandy bottom that created the conditions for developing anoxic zones.
This was first called the Jaubert Method, and later it was changed to simply DSB: it adopts a think layer of sand without building a reduced circulation area; it also adds living rocks, but in smaller number than the Berlin; and the skimmer. In this way it creates what is commonly called DSB: Deep Sand Bed.
I think that at the end the answer is easy to spot. The DBS is like the Berlin except for one difference: a part of the living rocks has been substituted by the sand as bacterial substrate.
The other elements are still necessary: lighting, active carbons, skimmer, restoration of calcium and carbonates, and strong movement.
Technically the only difference is the proportion of rocks to sand substrate.
In truth, the quantity of sand in aquarium used in a DBS is huge compared to the quantity of rocks in the Berlin Method. In fact, the sandy lay should be 12 cm in order to let the anoxic conditions form: it’s for the denitrification, that is the split of the nitrates into nitrogen and oxygen. In order to do a real comparison we should use in both aquariums the same weight of filtering material.
If we compare an aquarium of 300 liters, we would have about 60 kg of living rocks (in a relationship of 1:5), reduced in the last years to 40 kg in the case of a Berlin aquarium, while for 12 cm of sand we should use, more or less, 72 liters of water (120×50 cm of base, 12 cm of height), that is 140 kg di sand.
As you can see the situation is quite different. On the one hand we have a bacterial substrate between 40 and 60 kg, 140 kg of sand plus 20 kg of living rocks on on the other.
That’s why the DBS not only seems, but actually is, more biologically efficient, because it uses a greater amount of substrate. If we used the same weight in kg the biological difference would be canceled.
Advantages and disadvantages of DSB compared to classic Berlin
But at this point we have a system with a higher biological efficiency, and also a greater weight, as well as a greater encumbrance in tank given by the sand. This leads to substantial differences:
- Greater biological efficiency in reducing the nutrients.
- Possibility of using a less performing skimmer.
- Greater biodiversity at the level of marine organisms given by the sand.
- Restricted choice of fish and marine organisms compared to the Berlin method, because you have to choose animals that don’t cause problems to the sandy bottom.
- The movement in aquarium becomes complicated, because it’s difficult to use a high flow that doesn’t create holes in the DSB.
- The aquarium should be higher than an aquarium without sand, caused by the layer of the DSB. This means that, with the same free space dedicated to fish and corals, a higher aquarium (10 cm at least), will be heavier, more expensive, and with thicker glass.
- Eventuality that the bottom doesn’t work biologically or that it may create a cohesive and thick layer.
- Longer maturation time.
Is there a winner? Well, at the end they’re the same thing, only the bacterial substrate and quantity changes. We know that the same volume of substrate will give us the same result, so we can give more importance to the sand for a more clean layout, but we must consider weight, costs, maturation, and movement.
What do you think? Let us know in the comments or on one of our social channels.