So after some more experimenting, I can see better how Rachio is doing it (I think, wrongly):
- The upper irrigation bounds for a scheduled run is based on the soil’s Capacity, which Rachio calculates as AW * Root Depth * AD, with the idea that you don’t overfill the soil.
- Full Capacity is AW * Root Depth
- However, the upper limit irrigation should be Full Capacity - Current Balance, with a minimum irrigation that brings it to Full Capacity * AD.