Noisy skimmer

If your skimmer makes loud noises, vibrates, or seems not to be working properly, it’s important to take action to avoid damage. Never clean the silencer with fresh water to remove salt deposits. This practice can damage the impeller. Never test the pump out of the water. The test water must be saltwater (35 0/00), never fresh. The pump must never be tested without the venturi and air tube installed, or with the intake facing downward.

Different noises

Different noises indicate specific problems, easily solved with a few simple actions. HISSSSSSSSSSS: The noise is caused by an air vortex inside the silencer. When air passes through a tube, it can create a whistling sound, especially if the flow is fast and the diameter is small. Solution: clean the silencer tubes thoroughly. GLOBGLOBGLO: The noise is caused by water accumulating inside the silencer. Frequent on/off cycles can cause too much water to enter. Solution: open the silencer and carefully empty it. VRRRRRRRRRRR: Normal noise caused by the shaft rotation. It can increase if the impeller is dirty or unbalanced. Solution: clean the impeller. TRTRRTTTRTRTR: The shaft moves axially and the impeller may hit the cover if there’s dirt or if the air intake is blocked. A misaligned rear bearing can also cause this. Solution: clean the venturi and the air intake tube thoroughly. VZZZZZZZZZZZZ: Typical of DC pumps. Electronic noise that may appear and disappear without reason, linked to speed, temperature, voltage, or dirt. Solution: try turning the pump off and on again, or slightly change the pump speed. UUURRRRRRRRR: During operation, the skimmer may generate vibrations that, when resonating with the aquarium structure, amplify the noise. Solution: try adjusting the pump speed. The problem is common in small square-based aquariums, with tall cabinets and crowded plastic sumps. Rubber feet under the cabinet or sump can help reduce vibrations.

Troubleshooting

To solve the issue, perform a full system check. Silencer: Remove the silencer and let the pump run only with the venturi and air tubing. If the noise disappears, the silencer is probably dirty. Venturi: If the venturi is clogged with dirt or salt, remove it from the pump and check that the air passage hole is clear. Use a toothpick to remove any buildup. After cleaning it, reinstall the venturi and restart the pump. Pump: Disassemble the pump and check the intake for debris or algae. Unscrew the prechamber screw and rotate it open using the supplied wrench. Remove the impeller and take out the two bearings, front and rear, using a small puller or hook. Even if it’s inconvenient, the rear bearing must always be removed to find the problem. Motor: Check the motor, especially where the impeller rotates. Make sure there are no cracks, grooves, or exposed metal parts. Check that the bearing seats are not deformed and that the power cable is not damaged or burnt. Impeller: Clean the impeller and check that it is not damaged. Make sure the ceramic shaft is not broken or chipped, and that the magnet has no bulges or scratches. Ensure the impeller is correctly mounted on the shaft and that the pins are not worn out. Make sure all components have been reassembled correctly, swapping the bearing positions to compensate for any wear that may be hard to detect. Finally, test the pump in saltwater with the venturi and air tube installed, to verify proper operation.

Still noisy

If the problem persists, the fault has been missed or not identified. The pump must be sent for service or replaced with a new one. Usually, it’s enough to replace the impeller and bearings, which are subject to normal wear. However, if the pump is more than 4 years old, it’s recommended to replace the entire pump, not just the impeller.