Your UV globe can still light up after 12 months, but that doesn’t mean it’s still working properly. The UV-C wavelength output drops off significantly once a globe passes that age, so it stops killing algae cells effectively, even though everything looks normal. Because of this, a filter that “should be working” can suddenly lose its ability to keep the water clear. If your pond keeps turning green despite a working filter, an old UV globe is often the cause.
Finding the Right Globe for Your Filter
UV globes aren’t interchangeable between wattages or fittings. Before you order, check three things:
Wattage, printed on your existing globe or your filter’s manual (common sizes: 7W, 9W, 11W, 18W, 24W, 36W, 55W, 75W)
Pin fitting, either a 2-pin or 4-pin configuration, depending on your filter brand
Globe length, because some filters use a shorter globe even at the same wattage
If you’re unsure which one you need, bring in your old globe or filter model number, and we’ll match it for you.
While You’re Replacing It
It’s also a good time to check your quartz sleeve, which is the glass tube the globe sits inside. These sleeves can crack or cloud over time, and that reduces UV output even with a brand-new globe fitted. If your filter needs replacing entirely rather than just the globe, we also stock UV filters for fish ponds.
Not sure what you need? Get in touch with your filter brand and model, and we’ll find the right match.