Spa makes loud banging or knocking noises when pumps run

Safety: Turn off power at the GFCI breaker before tightening hardware or opening unions.

• Bleed air: Loosen pump unions to release trapped air, then retighten.
• Check water level: Ensure water is high enough to prevent air ingestion at skimmers.
• Tighten mounts: Verify that pumps are securely bolted to their bases and that any vibration pads are intact.
• Inspect plumbing: Look for loose PVC pipes or fittings that may be striking the cabinet when pumps start.

Persistent loud noises may indicate internal pump damage; consider pump replacement if noise does not resolve.