Thanks in advance for all suggestions. I have 2 separate irrigation systems watering 5 acres. Originally 1 system irrigated from the well and the 2nd system around the house was on city water because of the rust from the well staining the house and cars. I started pumping the well water into the pond and pumped out of the pond for irrigation to eliminate the rust and connected both systems. For the 2nd summer the well has gone dry in the hot months. I now have to use city water for both systems until October when the well produces again. I have a master valve on the original city water system. To be able to use both controllers I used isolators to connect the controllers together. The 2 cables that connect the controllers together are connected to the p/mv terminals and the common terminals on each controller. I tried attaching the original mv wire back on the same terminal but it doesn't open the valve. I have a separate transformer connected to the valve to keep it open, but it is a lot of trouble to turn it off and on when needed. The system is old and leaks often so I need to keep the water off the system when not needed. Is there a dependable timer I can install on the mv to open with the controllers or another way to wire it in the controller?