Philips PLL UV Bulb
Philips PLL UV Bulb are available in 18w, 24w, 36w and 55w sizes and are compatible with most brands of UVC. The Standard replacement UV lamps have 4 small pin connections at one end of the bulb.
To keep your pond clear from algae and green water build up bulbs should be replaced every 8 to 12 months, the recommended time to replace a bulb is at the start of spring just as the pond season starts, this ensures the UVC is at optimum performance for when it is needed.