Items to check:

This condition is usually due to an air leak within the plumbing system that causes bleed back through the main drain. Check other items referenced or call for repairs.

1. Leak at suction side of pump.

2. Water level too low.

3. Skimmer weir stuck.

4. Leak at pump hair and lint lid. Remove, clean “O-Ring”, lid o-ring seat and pump o-ring seat. Reseal pump lid.

5. Bleed air off filter after backwashing.

6. Ripped or torn grid.