OASE UVC lamp 7W - fits Filtral 700 and Cleartronic 7W It is recommended to replace UV bulbs after one year of continuous use. If the unit is only used 6 months out of the year, as with outdoor ponds, the bulb can easily last for 2 seasons. Take care when replacing your bulb not to touch the glass with your bare hands. This is because the oils on your fingers can reduce the life of the bulb.