Reliably kills floating algae and harmful bacteria: The UVC 15 W replacement lamp is characterised by its high quality. As the UVC pre-clarifier with a power consumption of 15 watts is usually in continuous use, the effect can diminish after approx. 8000 hours. We therefore recommend replacing the lamps at regular intervals. It is best to do this in the spring so that your primary clarifier is ready for the whole pond season. Suitable for all Oase UVC devices with 15 W.