If a pump supplies water for more than 1 tank, then it will be controlled using pressure based solenoid valve system.
Controlling multiple pumps using time switches is customisable. This system will control the pumps alternatively or both at a same time.
This system works with the help of level sensor fixed in OHT. That sensors will decides which pump should start first. This system is feasible when both the pumps supply the water to a single tank.