SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

We just had our irrigation system done on our 1 acre property. I wanted to get an internet controller for more flexibility, etc. But the company that did the install, rightly so, wants to use their controller - RainBird. We have 9 zones, 1 of them being a garden, and a few others with sod. So I really wanted the ability to make more complex watering schedules/times. Can I wire up both controllers to the valves? The company that did the install have never done this but did not see a problem with it. I have a decent understanding of electronics and see no problem other than maybe feedback from the active controller into the non-active controller. Although, I would think since the controllers are controlling wires that are underground exposed to the elements, there might be some built in protection.