To facilitate this, there is a power port to the left of the float switch cable into which a 10V power source can
be connected. This power supply can be linked to either a simple timer or to an aquarium computer and
used to hold off the reactor from dosing during part of the 24-hour cycle.
When the 10V supply is applied the activity LED H will flash red/green and the controller prevents the supply
pump from adding any water to the reactor however all of the other pumps, solenoids and functions
continue to operate as normal.
It will be necessary to allow for the hold off period when calculating the flow rate required, for example; if
the normal flow rate required was 60 litres per day for continuous running and the reactor was stopped from
dosing for 12 hours of the 24-hour period, then it would be necessary to set the flow rate to 120lts.
Running the Twin-Tech reactor for the first time
You should now be ready to run the reactor for the first time, go through the following checks.
•
The unit is completely full of water and bled of any air in the pump.
•
The end of the outlet hose is in the sump or tank
•
The CO2 system is connected, and the pressure is set to 1.5-2.0 bar.
•
AT THIS STAGE LEAVE THE MAIN VALVE ON THE CO2 BOTTLE CLOSED.
•
The feed pump is in the tank water. Squeeze the filter sponge to remove any air.
•
All wires are connected to the pumps and the float switch is plugged into the controller.
•
Set the initial flow rate to 50lt/day
•
Set the recirculation rate to 50%
•
Set the initial bleed rate to 50lt/day.
Plug in the power
The main LED will display a series of numbers as the system initiates and then the recirculation pump will
start to run.
IMPORTANT:
At this stage you should be able to observe the water recirculating around the reactor. If this is
not the case, then you have not correctly removed all of the air from the recirculation pump body. Remove
the power from the controller and bleed the reactor again.
If the water is observed circulating around the reactor then you will also see the blue light on the controller
illuminated as the system requests CO2. Now open the main valve on the CO2 bottle and you will observe a
large pocket of gas starting to form in the top of the gas chamber. This will slowly grow until the bottom of
the pocket reaches the level of the float switch and should happen over a period of 60-120 seconds.
If the gas pressure from the regulator is too low so that it takes more than 4 minutes to trigger the float
switch, then the unit will alarm. Increase the pressure slightly on the regulator and briefly unplug/re-plug in
the controller and it will start again and refill correctly.
If the pressure is too high, then the pocket will fill too quickly which may introduce too much gas in during
normal operation when the system is only asking for top up additions.
The reactor is now running normally
.
Observe the system operating and you will see the feed water come on every 5 minutes or so, this will allow
the CO2 to dissolve in the new volume of water. The pocket of gas will get smaller until it reaches the upper
float position, at which point it calls for more gas, the blue LED will come on as gas is added, refills and
triggers the float again, the blue light goes off.
Generally, you will not observe the de-gas cycle operating as it will happen automatically in the background.
Measuring the dKH of the effluent.
Leave the reactor to run for a couple of hours and then measure the dKH coming out of the effluent. This will
normally be in the range of 40-60dKH.
Most test kits only read up to 16dKH for a full syringe of reagent, however if you add a second syringe it is
32dKH, and so on. Keep going until you reach the end point and then all of the numbers together.