During the dry months of the year it is important to recirculate rainwater tanks to help kill bacteria particularly when the tank water level is low. Using a basic irrigation computer and a solenoid valve, recirculating water can be achieved automatically on a regular basis. The system can be switched off during the wet months.
Water should return into the tank through a high volume sprinkler head to avoid disturbance of sludge at the bottom. Recirculating water one and a half to two hours once per week is sufficient time for a 90,000 litre (20,000 gal) tank while half an hour is sufficient time for a 5,000 litre tank.
The Ecovortek unit must be kept at least two metres away from any mains electrical appliance including any pumps. Solenoid valve working at lower voltage must be kept at least 300 mm away.
The solenoid valve must be programmed to switch on at least once each week to recirculate rainwater. As water is recirculated it sucks air through the venturi to aerate the water. Once the solenoid has switched off the venturi must drain the water left in the recirculating pipework. Draining the return pipe avoids bacteria growth in the water during the week.