I have a zone that’s sandy loam with shallow roots as it’s newer grass and the Flex daily looks like it is going to water it way to much. For some reason a large area of that zone stays very wet for a couple days after it rains. It’s like the sand doesn’t absorb it nearly as fast as you’d think. It may be a compaction issue.
What can I adjust to make it water less often? I’m afraid the roots will rot.
Sounds like there’s more available water than the default Available Water Content setting for sandy soil (0.05). You can trial increasing the AWC under advanced zone settings. Maybe try 0.10. That’s a big change. May take a few watering cycles to find a reasonable AWC for your unique soil. Root depth setting change may be necessary but sounds like you already know for sure what that setting should be.
Compaction does make things challenging since NRCS AWC values will only be a starting point. There could also be a hard pan layer under your top soil, which would restrict infiltration of water and keep water at the top of the soil.
You can try the NRCS web soil survey to see if they have a better value for AWC. See this post for instructions: