Community consensus strongly advises against buying generic "unbranded" bulbs from marketplaces like eBay, as they are often reported to be ineffective or even scams.
“Pentair formerly Emperor Aquatics [is] the best. Many are uv lights wishing to be a sterilizer when they grow up.” where to buy uv bulbs
: Ensure the pin configuration (e.g., 2-pin G23 or 4-pin) matches your specific fixture exactly. where to buy uv bulbs
: Never look directly at a lit germicidal UV bulb, as UVC radiation can cause severe eye and skin damage. where to buy uv bulbs
“The best 55w UV bulbs are jointly Phillips and Osram... I have two 55 watt UVs and only buy Philips bulbs now after buying cheaper ones that were crap.” Koi Forum UK · 5 years ago