I am just designing my drip irrrigation system and thought that it would be a good idea to water mainly with hard water to save softener salt and then switch to softened water for a couple of minutes before shutting off each zone, so that hard water will not be left in the drip emitters to evaporate and clog them. It seems that this would be common practice for people with a water softener, but I’m not sure how to do it. Sounds like two master zone valves, hard and soft, would work, though, if I understand the concept of master zone.