When your robot is clearly running but debris is still on the floor, the problem is almost always in the suction and filtration path.
The Filter Is Full or Wrong for the Job
A packed filter has nowhere to put new debris, so it simply pushes dirt around. Empty and rinse it before every cycle. Just as important, match the filter to the debris: coarse cartridges let fine silt and sand wash right back out. For fine particles, algae, and dust, upgrade to NanoFilters, which capture far more than standard media. Not sure which to use? See our guide on what filters to use in your pool robot.
Trapped Air Killing Suction
Air pockets in the impeller housing gut the robot's suction. Submerge the unit on its side and tilt until the bubbles stop before starting a cycle.
Worn Brushes and Impeller
Brushes agitate stuck-on debris so it can be drawn in; when they are worn smooth, pickup drops. Inspect the brushes and the impeller for wear or blockage and replace parts from our parts page.
When the Robot Is Simply Underpowered
Lightweight budget cleaners struggle with heavier loads. A strong corded robot like the Dolphin Sigma pairs powerful suction with active scrubbing to lift debris that weaker machines skim over. Compare pickup performance in our best robotic pool cleaners roundup.
