I love ESPHome. The declarative language makes it fun and easy to do so many little tasks like this. Used with Home Assistant it makes it easy to create graphs of everything. Do I NEED to know how much water my tree consumes? No, but I like seeing it anyway!

When controlling physical systems I try to limit the damage they can do with simple interlocks. For instance, the relay I added to control my central heat is in series with a conventional thermostat which is set for a few degrees above pleasant.

Likewise, you can splice a float switch in line with the pump's power cable, positioned so it will cut off power if the water level nears the top of the tree stand. This will prevent the flood when the software decides to rebel against you.