Once the nitrate has been reduced to zero
This section is relevant to all methods of operation
Once the nitrate level within your system is under control you will not require the same amount of denitrification however each day there will be nitrate added to your aquarium from your fishes and food. At this stage you should run the filter at a tick over level, (unless it is being used on a system with a heavy load that requires the unit to continue to run at its optimum flow).
It will be necessary to reduce the amount of water passing through the reactor and at the same time the amount of food.
For the manual injection system, reduce the volume of Nitrate Fluid that is injected by 10% each time in a series of steps and reduce the flow rate by the same amount. Nitrate bags can be partially filled and operated for the same 4 week period and the peristaltic pump can simply operate for a shorter period of time each day.
Monitor the nitrate from the reactor to ensure that it is still maintaining a zero reading from the outlet and if not then and slowly reduce the flow rate until it is in balance with the volume of nitrate food that is being added. Keep on reducing the feed rate and flow until you start to see nitrate appearing in the tank. This is just below your equilibrium level for your system.
Rebalance the reactor at this point and try to maintain your nitrate level at 1-2 mg/lt and certainly less then 10 mg/lt. If the nitrate remains at zero then it may be necessary to reduce the feeding and flow further until a low level appears found in your system. If this level starts to rise then you need to increase the flow and feeding accordingly.
It is possible to just switch off the reactor however you will need to go through the maturation period again once the nitrate level rises with time. Another benefit of maintaining the operation of the nitrate filter is that the bacteria release trace elements back into the water which can be beneficial especially to corals.