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3. Theory
In the Aqua Medic Sulphur-Nitratereductor, the aquarium water is treated under oxygen
conclusion. With the absence of oxygen, many bacteria are in the position to use nitrate as
replacement of oxygen for breathing.
The oxygen is used for respiration, the nitrogen is separated into the water. Nitrogen gas (N2) is
completely harmless as a natural component of air.
Thus, the decomposition of nitrate is a pure breath procedure. Additionally, also the bacteria need
food as any other organisms. For this reason, the nitrate-reducing bacteria must be fed. The
sulphur beads serve as food which are used at the same time as settlement substrate. Sulphuric
acid develops as a waste product. In order to neutralize this, the Sulphur-Nitratereductor contains
calcium carbonate (Aqua Medic hydrocarbonate, coarse grain). The developing sulphuric acid is
converted into calcium sulfate, which enriches itself in the water in the long run.
In a saltwater tank, calcium values up to 800 mg/l are possible. At the same time, the carbonate
hardness sinks. For this reason, the carbonate hardness has to be controlled regularly. With a
carbonate buffer (Aqua Medic Reef Life Calcium Buffer Tabs), the used up carbonate hardness can
be supplemented. Nevertheless, a regular water change will be necessary so the concentrations of
sulfate and calcium remain in the correct range.
In a freshwater tank, the total hardness is constantly increased by the Sulphur-Nitratereductor. If
this unit would be used without calcium carbonate, the carbonate hardness and the ph-value would
drop.
The flow rate through the Sulphur-Nitratereductor is very slow. This is the main difference to other
aquarium filters where the water is often treated once per hour or even more often.
4. Working principle
The
Sulphur-Nitratereductor
SN
Blue
is supplied with water from the top. The flow rate should
be adjusted that way that the outflowing water is nearly free of nitrite and nitrate (approx. 0.5 l/h).
The flow rate can be adjusted exactly by the dosing pump SP 1500 (max. 1.5 l/h, not included) and
a timer (not included). If the reactor is to be connected in a bypass, the adjustment of the flow
rate has to be done manually. The circulation pump placed in the lid of the reactor circulates the
water internally.
The outflow is located at the top of the filter lid. From there, the water flows back into the
aquarium or filter tank.
5.
Set-up
This version of the
Sulphur-Nitratereductor
SN
Blue
is a closed system that can also be run
without a sump based filter. The system is pressure-resistant up to 0.2 bar (2 meter water head
height). Operation in the base of a cabinet is thus safely possible.
The filter can be installed below the aquarium from where the water can flow into a filter chamber
or back into the aquarium.
Important: Never close the in and outlet of the filter completely since overpressure will
arise from carbon dioxide supply!
6. Starting
The
Sulphur-Nitratereductor
SN
Blue
is closed with three clamps (16). Before filling, it has to
be checked that the
sealing (7)
is perfectly inserted and all clamps are firmly fixed.
The baskets (2) for holding the hydrocarbonate and sulphur beads have to be inserted correctly.
The thorn which is placed at the bottom of the basket has to be put in the pipe of the lowest
basket. Opposite the pipe, there is a groove into which a guide rail attached to the inner side of the
container clutches. The lowest basket may not tilt, otherwise the reactor can not be closed. The
two other baskets are put on in such a way that the pipes are on top of each other. Each pipe has
