A water tank that's too small turns mopping into a relay race

A water tank that’s too small turns a mopping run into a relay race — your robot shuffles back to the dock three or four times to refill over the course of a single cleaning session, stretching what should be a one-hour job into something much longer. It’s worth checking the tank capacity against your floor plan before buying, because the difference between a 200ml tank and a 400ml one is the difference between seamless cleaning and a robot that keeps interrupting itself.