Dolphin pool cleaner running but not cleaning

dolphin

The Problem

A Dolphin that drives around the pool but leaves it dirty is moving but not vacuuming or scrubbing effectively. The filter, impeller, or brush system is not working correctly — most commonly a blocked or improperly seated filter.

Steps

1
Remove the filter basket and inspect it. Clean if more than one-third full. Replace if torn or with holes.
2
Reseat the filter and confirm it clicks or locks into position. Any gap between the filter and its housing creates a bypass.
3
With the filter removed, check the impeller area for packed leaves, hair, or debris. Clear any blockage with running water or a narrow brush.
4
Check that the brushes spin freely. Remove hair or debris wrapped around the brush shaft.
5
Return the robot to the pool and run a fresh cycle. Lift it out horizontally at the end of the cycle to avoid spilling the filter contents.
💡 Use the handle to lift straight up — do not tilt until the robot is clear of the water surface.
6
If the pool is still dirty after a fresh cycle with a clean filter and working impeller, run a second cycle.

Possible Causes & Solutions

common

Filter basket is full, torn, or not correctly seated

A filter more than half full blocks suction. A torn mesh lets debris bypass the basket. A filter that is not clicked into position creates a gap that debris flows straight through. Clean, inspect, and reseat the filter.

common

Impeller clogged with leaves or hair

The impeller drives water flow through the robot. A blocked impeller dramatically reduces suction even with a clean filter. Open the filter bay and check the impeller area for packed debris.

occasional

Brushes not spinning, leaving debris unagitated

Brushes scrub debris loose before the impeller vacuums it up. If the brushes are stationary, debris remains on the pool surface. Check for hair wrapped around the brush shaft or a broken brush belt.

occasional

Robot lifted incorrectly, dumping debris back into the pool

Always lift the robot horizontally and keep it level until it is fully out of the water. Tilting the robot during extraction causes the filter contents to empty back into the pool.

occasional

Pool debris load too heavy for a single cycle

After very heavy leaf falls, the filter may fill before the robot finishes. Run a second cycle or clean the filter mid-cycle on heavily loaded pools.

When to Replace

Clean the filter after every use. Replace the filter when the mesh is torn or when suction does not improve after thorough cleaning. Replace the brush assembly if bristles are worn flat.

Where to Buy

Find compatible replacement parts from these retailers:

Check price for dolphin replacement parts on Amazon

Compatible Parts

Dolphin Replacement Filter Basket

Fine and ultra-fine mesh options available. Confirm compatibility with your model.

Dolphin Replacement Brush Set

Brush mount type varies by model — confirm before ordering.

Frequently Asked Questions

My robot drives fine but the pool is still dirty. What is wrong?

Check the filter first — it is almost always the cause. A full, torn, or unseated filter is responsible for the vast majority of "running but not cleaning" complaints.

Does the robot need to be cleaned after every use?

Yes. The filter should be rinsed and cleared after every cycle. Running a dirty filter in the next cycle reduces suction immediately.

Can I run the robot without the filter to clear a heavily loaded pool?

No. Without the filter, debris passes through the impeller and is redistributed into the pool. Always run the robot with the filter correctly installed.