I have a similar situation as described by a couple other users. I have 8 zones that i need to alternate watering between two different sources. I need to feed all 8 zones from a ‘nutrient’ source and then feed all 8 zones from a ‘flush’ source. The workaround described above won’t work because i have too many zones. I will try the parallel workaround next. Just hoping this is being worked on for the next update? Two master valves that can be controlled within a program and associated with any zone. Thx!