Aqua Medic SN 400 Mode D'emploi page 12

The biochemical conditions in the Sulphur-Nitratereductor differ completely from those in the
aquarium: Nitrate has to be reduced to nitrogen gas. This is only possible if there is no oxygen
dissolved in the water. The redox potential is low or even negative. The ideal range is between -50
and -250 mV. If it exceeds -50 mV, the denitrification reaction may stop at nitrite stage!
Controlling the Sulphur–Nitratereductor
If the redox potential exceeds -50 mV or even gets positive, the flow rate should be decreased.
Warning: Danger of nitrite!
8. Failures
Problems with denitrification are mostly caused by wrong adjustment of the flow rate. They can
only be determined by measurements of nitrite and nitrate concentrations in the filter or by
measurements of the redox potential.
- The pump makes noise: If the pump housing contains air or gas, this causes a strong noise.
In this case, the pump is pumping little or no water and its cooling is insufficient. The pump
may overheat and be destroyed. The housing of the pump has a small hole where air and gas
can escape. If this hole is blocked, it has to be cleaned with a needle.
- Nitrate or nitrite in the filter's outlet: 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 rates,
decrease flow rate.
9. Warranty
Should any defect in materials or workmanship be found within 24 months of the date of purchase
AB Aqua Medic undertakes to repair, or at our option replace, the defective part free of charge –
always provided the product has been installed correctly, is used for the purpose that was intended
by us, is used in accordance with the operating instructions and is returned to us carriage paid.
Proof of Purchase is required by presentation of the original invoice or receipt indicating the
dealer's name, the model number and date of purchase. This warranty may not apply if any model
or production number has been altered, deleted or removed, unauthorised persons or organisations
have executed repairs, modifications or alterations, or damage is caused by accident, misuse or
neglect. Please note that the product is not defective under the terms of this Warranty where the
product, or any of its component parts, was not originally designed and / or manufactured for the
market in which it is used. These statements do not affect your statutory rights as a customer.
AB Aqua Medic GmbH - Gewerbepark 24 - 49143 Bissendorf/Germany
Current manuals are available for download at www.aqua-medic.de.
- Technical changes reserved - 07/2017
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