UV bulbs are a key component of UV sterilisers; without them, your steriliser won’t be able to reduce pathogens or algae. It is essential that you start checking your UV bulbs after about 6 – 8 months of use. After that, the bulb will not work to its full potential, and you will notice the ramifications in your tank.
Replace them: every 6 – 12 months.
For more information on when to replace aquarium filter parts, see our blog post.