You can use capacitive water sensors taped to the outside of non-capacitive containers (aluminum foil, a resistor, an arduino, and a plastic 5 gallon container), but honestly all you need are DNI timers to "automate" any grow operation. Put your lights and pumps on a schedule and there is absolutely no reason to get more creative. If you do anything besides low-level timers you're making it complicated and brittle with no added benefit.