Fholbert:
What you're describing is exactly why I have ordered a BlueSpray controller. I presently have 2 separate controllers and run into the problem of trying to avoid overlapping times between them (I'm on a well).
In the BlueSpray user guide, it has this information:
On the controller under Settings tab, click on the Operations tab. Look for the Stack runs option.
The manual gives this description:
In Stack mode, overlapping runs will be rescheduled to be run sequentially. Otherwise, they will be run in parallel. Note that if you schedule concurrent runs, you may not have enough pressure to water your lawn properly. Residential users should typically choose Yes for Stack mode.
It looks like you can also you the "Seasons" feature to add a percentage of time to all your watering zones in one easy step. It looks like you can only go up to 140%.
The manual gives this description:
Percentage. Enter the water budget for the season. The percentage applies to the run time configured. For example, if you set 100% for the summer and 50% for the fall, and each zone to run for 10 minutes, then the controller will run the full 10 minutes in the summer and 5 minutes in the fall. A percentage ending with a 5 is rounded up. For example, 55% will run for 6 minutes.
