Missed areas usually come from cord drag limiting the robot’s reach, a cleaning cycle that’s too short for your pool size, weak "random" navigation, or a full filter that stops the robot from picking up. Extend the cycle, free the cord, empty the filter — and for reliably complete coverage choose a robot with mapped, gyroscopic navigation.
Run the quick checks
- Cord length/drag: if the cable is too short or tangled, the robot can’t reach the far end. Uncoil it and add a swivel.
- Cycle time: a large pool may need the extended cleaning mode to cover everything in one run.
- Full filter: once the basket fills, the robot stops collecting even where it drives — clean it after each cycle.
- Placement: dropping the robot in the same spot every time can bias its path; vary the start point.
Navigation is the real difference
Entry-level robots bounce around randomly, so coverage is luck of the draw and the same corners get skipped every time. A robot with a gyroscope and smart scanning knows where it has already been and drives systematic, overlapping rows. The Dolphin Sigma maps your pool for edge-to-edge coverage of the floor, walls, and waterline.
Odd-shaped pools
L-shaped, kidney, and freeform pools challenge random cleaners the most. If your pool has lots of nooks, prioritize mapped navigation and a longer cycle. Compare coverage-focused models on our robotic pool cleaners page or see the best pool robots for full coverage.
