Pump makes a loud cavitation or rattling noise and pump basket shows lots of air bubbles.

Safety first: Turn off pump before adjusting valves.

• Step 1 – Open valves fully: Ensure all necessary suction valves are fully open to maximize water supply to the pump.
• Step 2 – Clean baskets and filter: Remove debris from pump and skimmer baskets and clean/backwash the filter to reduce system resistance.
• Step 3 – Reduce RPM: Lower the pump speed to a level that provides adequate flow without causing cavitation. Variable‑speed Pentair pumps allow fine adjustment.
• Step 4 – Check for suction leaks: Inspect and tighten suction unions, pump lid, and drain plugs. Air leaks can exacerbate cavitation.