I don't want to join the reservoirs by pipes at the bottom as then a small leak that form might encourage a larger leak, and continously put out water. The last tube with the float should really be linked by the top as well, and have a tiny hole at the bottom. Then the water starts up every now and again, ensuring everything is filled, the final tube fills up, the stop switch is triggered, and the last tube empties slowly, expelling a small amount of liquid. The system is then ready to go for the next fillup.