Reliable light output for Bitron C 24 W and FiltoMatic CWS 12000: The UVC 24 W replacement lamp is characterised by its high quality. As the UVC pre-clarifier with a power consumption of 24 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 spring so that your pre-clarifier is ready for the whole pond season.