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8. Failures
Problems with the denitrification are mostly caused by wrong adjustion of flow and feeding rate.
The causes can only be determined by measuring the nitrite and nitrate concentrations in the filter
or by redox potential.
-
Pump makes noises: If there is air in the pump housing, there might be a loud noise. Since
then the pump only forwards little or no water at all, the necessary water cooling is missing.
Then, the pump might overheat and fail. The plastic angle at the pressure side of the pump has
got a small drilling where existing air can be squeezed out. If the drilling is blocked, just clean
it by using a needle.
-
Nitrite in the outlet of the filter: If the outflow of the filter contains high amounts of nitrite, the
feeding rate is too low: Increase the feeding or lower the flow rate. In this case, most of the
times, the redox potential is too high (more than - 50 mV).
-
Nitrate in the outlet of the filter: High residual concentrations of nitrate often occur together
with high nitrite values.
Caution!
Most nitrate tests are disturbed by high nitrite
concentrations!. In this case, the redox potential is also too high - increase feeding rate,
decrease flow rate.
-
Hydrogensulfide in the outlet of filter: The filter smells like fouling eggs. In most cases, the
redox potential is too low (less than – 300 mV). Reduce feeding, check the flow rate and
increase it, if necessary. Ideal is a redox control with connected membrane pump, see
„Options“.
9. Mounting the filter
The cabinet filter system Marin 1000 is being delivered ready to use in a glass tank. This tank has
the dimensions 54 x 36,5 x 35 cm and can be placed in the cabinet of a standard aquarium with an
overflow chamber or an overflow box. As it is an open filter system, the cabinet should be of a
water proof construction.
Water inlet to the aquarium: The piping from the aquarium should be installed with PVC pipes of
40 mm diameter.
Suction pipe of the pump: The pump is best placed beside the filter tank. As suction pipe to the
pump, a pipe of 32 mm diameter should be used.
The pressure pipe back to the aquarium is installed with a bypass to the Nitratereductor. The part
between pump and bypass T-piece should be installed with a flexible hose to minimize any
vibrations that may be directed from the pump to the pipes. From the bypass T piece to the water
inlet into the aquarium, a PVC pipe may be used.
