Sadly, the reservoir fill level sensor has proven to be unreliable. I was planning to use a voltage measurement over a voltage divider, which is influenced by the number of gold contacts covered in water. It's starting to go crazy when the pump is turned on.
That's the reason why I implemented configuration options to disable battery monitoring and/or reservoir fill level monitoring. If one is disabled, it will not take part in the decision if an irrigation should take place or not. This not only allows continuing with the development regardless of the fill level sensor, but it also adds more flexibility in the hardware setup.
One other missing piece in the software is proper SNTP handling. The control logic requires to be notified of changes in the system time to work properly. Manually setting the time through the debug console is no problem at all, because I have all the software under my control. But the SNTP implementation is part of the lwIP stack used in the ESP-IDF. It doesn't signalize any state changes at all. According to a discussion on Github, I'm not the only one needing such a feature and it looks like it's already in development. I hope it will go public soon. Otherwise, I would have to patch the ESP-IDF sources, which would not be publicly available.