Aqua Medic Nitratereductor NR 1000 Mode D'emploi page 11

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It is, however, necessary to increase the metabolism of the bacteria so that they can reduce
enough nitrate. For this reason, the nitrate removing bacteria have to be fed with organic
substances. The food Denimar contains organic substances that can be used completely by the
bacteria. The only waste product is CO .
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The flow rate through the 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. The water in
the Nitratereductor should have a retention time of 4 hours. It is, however, sufficient to treat it
once per week. If the filter is adjusted correctly, the water leaves the filter nearly free of nitrite and
nitrate.
4. Description of the Nitratereductor
The AB Aqua Medic Nitratereductor consists of a reaction vessel (1) of 10 l volume. To provide
surface material for bacteria, the filter is filled with AB Aqua Medic Bactoballs (2). They create an
ideal microclimate for denitrification.
To avoid dead zones, the water is recirculated internally in the Nitratereductor. A recirculation
pump (7) is placed in the top.
In denitrifying filters, especially in units where the water has to pass through a long way, it can
occur that there is no even flow in the filter. Zones with a very low redoxpotential are created
where hydrogensulfide is produced (the filter starts to smell badly). On the other side, zones with a
rather high flow may arise where nitrate is reduced only to nitrite. In each case, the conditions
vary in the different zones of the filter and it is nearly impossible to find its right working point.
These unpleasant effects are avoided by the construction of the AB Aqua Medic Nitratereductor.
The recirculation ensures a complete mixing and the same redox potential level in the whole filter.
Zones with a very low redox potential and the production of hydrogen sulfide are avoided.
The redox potential can be used for the control of the filter. The effectivity and the reliability of the
filter can be increased.
Connections
The following connections are located at the Nitratereductor:
1. Inlet (5): There, you can connect a 6 mm air tube. At the inflow, you find an adjustion valve to
adjust the flow rate. The best value is approx. 1 – 1.5 l/hr (approx. 1 drop per second). The
adjustion at the inflow causes a delay until you can read the adjusted drop number at the drop
counter (14) at the water outlet. The drop counter is mounted inside the aquarium, close to the
water level. If the flow rate is regulated in the outlet, the valve may not be closed completely in
order to allow produced nitrogen to escape. During the start phase in the first weeks, the outlet
valve should stay completely open. The inlet has an internal elongation that prevents that gas
enters the inlet tube.
2. Feeding: Through this opening (4), you can inject Denimar-Powder with a syringe to enhance
denitrification. Dissolve the powder beforehand in some water. The valve has to be cleaned and
closed after every feeding.
3. Redox electrode: Through this opening, (17) you can put the pressure resistant ORP electrode
with standard thread (PG 13,5) Aqua Medic No: 220.18.
4. Outflow to aquarium (14): There, you can connect an air tube 6/4 mm, preferably a black
one to prevent algae growth.
5. Set-Up
The Nitratereductor is a hermetically closed system. The produced gas (nitrogen and CO ) can
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escape through the water outlet. For this reason, the outlet should never be completely closed,
because an eventual overpressure may escape through the water inlet and interrupt the inflow.
The Nitratereductor has to be placed in a way that the water can flow off either directly back into
the aquarium or into the filtration chamber. In a seawater aquarium, it is advantageous if the
outflowing water is flowing into the inlet of the protein skimmer or the trickling filter. In the protein
skimmer, the water is saturated with oxygen before it flows back into the aquarium.
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