I’m getting started to implement an application with Drip irrigation, simple 4 zones. I wanted to check if it is possible to have a valve output control a fertilizer valve in a venturi setup. What would be the most effective way to setup the fertilizer channel, just to overlap with each of the zones watering times. Will a master zone work in this case?
What I did was to have two master valves. One for regular watering and another for fertigation. I use the OSPi. I have OpenSprinkler configured to use the regular valve and then when I want to fertigate, I use a cron job to call a Perl script (could have been a shell script) that shuts down OpenSprinkler and takes over to do the fertigation and then fires OpenSprinkler back up. Fairly easy. Don’t really like shutting off OpenSprinkler, but necessary to keep it from messing with the valves.
What I plan on doing is using a Injector Pump (Stenner 85MHP40) on zone 1 activated by a 110v relay. It will be plumbed in my main feed line just before any zone solenoids. It will not be set as a master pump, just a regular zone named Fertilizer Pump and not set to sequential. When I create a watering program for any zone that I wish to fertilize, I include zone 1 with the time set to a few minutes less, that way it cleans out the fertilizer in that zone line. I can also create a program to water the same zone without fertilizer, I just don’t include zone 1 in that program. Hope this helps.
Sorry, I just noticed that the demo.opensprinkler names had changed before I did the screenshot. Zone 1 should be named Fertilizer Pump and Zone 2 named Banana Trees.