My house came with an existing Rachio installation for 10 zones. One of the first things I did once I started optimizing water consumption of the system was converting the existing fixed schedule to flex daily. When I created a Flex Daily schedule and saw the total run hours being in double-digits I freaked out and adjusted down the total time by a factor of 2 or 3.
Now that I have a somewhat better grasp on Rachio, I’m starting to wonder about the ramifications of that adjustment. As far as I understand the algorithm now, decreasing the total “daily” run time should simply increase the frequency of watering because the fundamental measure of how much water is needed hasn’t really changed. Is this understanding correct?
If so, that also means that instead of minimizing water use, I’m actually making things worse over the long run by keeping the runs shorter than needed and not letting water propagate to the levels specified by the root depth setting (i.e. keeping water near the surface where it evaporates faster, plus not training the plants to be more drought resistant). Am I on the right train of thought here?
Fundamentally yes, you are doing your yard a disservice by watering for shorter duration more frequently. The goal of “correctly” watering is to promote a deep root structure that allows the plant to be more drought tolerant.
Thanks. So just to confirm, if I recreate the Flex Daily schedule and let it be as is (without shortening the proposed run time), will the water usage (say over a week or a month) remain the same as with my currently shortened schedule? I really don’t want to be surprised by the next water bill 
Changing from a Fixed Schedule to a Flex Daily schedule may very much result in a surprise in the amount of water used. Your Fixed schedule has probably been fine-tuned to provide a reasonable amount of water over time (unless it’s new of course), while the Flex Daily schedule will determine the time based on the value of Nozzle Inches per Hour, which can often be wrong in my experience.
If you want to compare your previous Fixed schedule with a new Flex Daily schedule, count the average minutes per zone of water with each during a week or so, and compare that, not just minutes for a single run. If they are greatly different, you may need to do some calibration or fine-tuning with Flex Daily. Don’t forget that Flex Daily will (and you should) provide more water in hot weather than in cooler weather.
