If the UV light in your external filter isn't working, follow these steps to troubleshoot the issue and restore proper function.


Important Safety Reminder

Always disconnect the mains electricity supply before handling or attempting any maintenance.
Refer to your product instruction manual for full safety and troubleshooting guidance.

Step 1: Inspect the Quartz Sleeve

  • Open the unit and carefully check the quartz sleeve that houses the UV bulb.

  • Look for hairline cracks, clouding, or any other damage that might allow water to enter.

  • If there are signs of water ingress, allow the unit to dry out thoroughly before testing.

Step 2: Check the O-Ring on the Quartz Sleeve

  • Examine the O-ring at the top of the quartz sleeve.

    • Ensure it’s not twisted, damaged, or dry.

    • Lubricate it lightly with aquarium-safe grease after each maintenance to maintain a watertight seal.

Step 3: Test the UV Bulb Using the Override Switch

  • Locate the override switch on the side of the head unit (black section).

  • Turn on the UV power, and then press the override switch to see if the bulb ignites.

    • Do not look directly at the bulb when testing.

    • If the bulb ignites, it might indicate that the filter casing isn’t making proper contact with the switch, which prevents activation.

    • You can gently reshape the metal clip on the switch to improve contact.

Step 4: Replacing the UV Bulb

  • If the bulb is faulty or damaged, check the size and type required for your unit.

  • You can find the appropriate replacement bulbs here.

Step 5: Refer to Our Extended Video Guide

For additional troubleshooting assistance, watch our Extended Setup Video starting from 5:30 minutes. This will visually guide you through the steps above and show you how to access key parts.

Step 6: Check the Filter Baskets and Magnetic Override

  • If the UV bulb still isn't working, try removing the filter baskets.

  • Reassemble them, ensuring the magnetic override on the canister does not align with the metal piece on the head.

  • Rotate the head 90 degrees at a time, which may help activate the bulb.

Still Not Working? Contact Customer Support

If the issue persists, please reach out to our Customer Service Team. Provide a short video explaining the problem to help us assist you more efficiently.

Safety Reminder

Disconnect the mains electricity before handling the unit. Always follow the instructions in the user manual (available on the main product page of the website) for proper handling and safety precautions.