Reaching the bottom of a deep pool and actually cleaning it are two different problems. Debris sitting eight or nine feet down has more water pressure pushing against it, so a robot with a weak motor might physically get down there and still fail to lift settled sand and dirt off the floor. The suction has to scale with the depth, not just the navigation.
Depth transitions add a second challenge on top of that. Most deep pools aren't a uniform depth throughout, they slope from a shallow end down to a deep end, and that slope can confuse a robot that relies on basic random-pattern navigation. Better systems plan their route around the pool's actual contours, so the transition between shallow and deep doesn't cause missed sections or a robot that loses its bearings partway down.
Cordless models deserve a second look here too. Retrieving a cordless cleaner from a shallow pool is a minor inconvenience; doing it from eight-plus feet down is a real chore, and battery life that's already tight can end a session before the deep end even gets covered. None of this replaces the other basics, either, a robot built for real depth still needs solid wall and waterline coverage, depth alone doesn't make a pool clean if the robot skips everything above the floor.
The Mammotion Spino E1 is a robotic pool cleaner from Mammotion, a brand best known for its wire-free robotic lawn mowers. Designed for residential pool owners seeking a largely hands-off cleaning solution, the Spino E1 is built to clean pool floors, walls, and waterlines in a single session, using intelligent path planning and adaptive climbing technology to handle sloped surfaces. It features a one-touch start interface with multiple cleaning modes and automatic waterline parking for easy retrieval, positioning it as a convenience-focused option in the robotic pool cleaner market.