5
To avoid dead zones, the water is recirculated internally in the
Nitratereductor
. A
recirculation pump is included.
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 bad). 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. Thes unpleasant effects are avoided by the constructionof
the
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. Inflow.
(needle valve [1]). 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 app. 10 - 30 l/hr. 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 of the aquarium, close to the water level.
If the flow rate is redgulated 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 elongiation, that prevents, that gas
enters the inlet tube.
2. Feeding.
Through this opening (3), you can inject Denimar with a sringe to enhance
denitrification. Dissolve the tablets/powder before in some ml of water. The valve has to be
cleaned after every feeding and closed.
3. Redox electrode.
Through this opening, you can put the pressure resistant ORP electrode
with standard thread (PG 13,5) Aqua Medic No: 220.18.
4. Outflow.
Here, you can connect a 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
2
)
can 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 direcly 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 oxigen, before it comes back into the
aquarium.
