Aqua Medic NR 400 Manuel D'instructions page 11

tablet food Denimar contains organic substances that can be used completely by the bacteria. The
only waste product is CO
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 at least. 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 NR 400
The Aqua Medic Nitratereductor consists of a reaction vessel (1) of 2.3 l volume. To provide surface
material for bacteria, the filter is filled with Aqua Medic Deniballs. They create an ideal
microclimate for denitrification. To avoid dead zones, the water is recirculated internally in the
Nitratereductor. A recirculation pump 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 redox potential 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 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 controlling the filter. The effectivity and the reliability of the filter
can be increased.
5. Connections
The following connections are located at the Nitratereductor:
- Inlet (4 and 5): Here, 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. 0.5 - 1 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 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.
- Feeding (4 and 6): Through this opening, you can inject Denimar tablets with a syringe to
enhance denitrification. Dissolve the tablets beforehand in some water. The valve has to be
cleaned and closed after every feeding.
- Redox electrode (3): Through this opening, you can put the special pressure resistant ORP
electrode with a special length and standard thread (PG 13,5), Aqua Medic No.: 220.19.
- Outflow to aquarium (7): Here, you can connect a tube 8/6 mm.
6. Set-Up
The Nitratereductor is a hermetically closed system. The produced gas (nitrogen and CO
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 interupt 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 comes back into the aquarium.
- Inflow: The inflow to the reductor can be realized as a bypass from the main circulation pump
with the included T-piece (8). The flow rate is adjusted by the valve (5) and drop counter.
should also put a tap behind the T-piece to get a higher pressure on the bypass to the reductor
by slightly closing it.
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