Dear customer,
Netro can manage multiple devices in one user's account and multiple Pixie timers can be controlled through the app as different zones and it does not require a controller. If you want to manually run the timers sequentially, you will have to switch between the pixie timers from the home page of the app to start watering. You can also create schedules for each timer to run them one after the other automatically. Please let us know if you have any further questions.
Thanks,
Netro Support