another benefit to what I just said above is the ease of changing irrigation times without having to adjust the injection dial. Normally if you increased your mater times, then you would have to decrease the injection so that you will not over feed the plants. By running with two manifolds, I can simply increase the run time of the second manifold and not have to worry about changing the settings on the injector.
Why do people not respect us as they do other tradesmen? Because every Tom, Dick, and Harry doesn't think he can be a plumber or electrician!