SunSun HW-303B canister filter 9-watt UV light bulb

The SunSun HW-303B canister filter uses a 9-watt UV light bulb with a G23 2-pin base to eliminate free-floating algae, bacteria, and pathogens. The ultraviolet (UV) system is built into the filter head and can be controlled via an independent, waterproof switch.

 Function and Operation

Purpose: Clears green water and reduces harmful pathogens without affecting beneficial bacteria anchored to filter media inside the trays.

Indicator Light: A small viewing window or indicator bulb lights up when the UV lamp is turned on and functioning.

Usage Tip: Running the UV light 24/7 is usually unnecessary; many hobbyists run it only a few hours a day or a couple of days a week to conserve bulb life.