The only thing that needs cleaning is the quartz tube. If there is a build up of limescale or algae on the tube, it needs removing so the UV light can reach the water. This can be done with mild non-abrasive cleaning agents or even vinegar.
The only thing that needs cleaning is the quartz tube. If there is a build up of limescale or algae on the tube, it needs removing so the UV light can reach the water. This can be done with mild non-abrasive cleaning agents or even vinegar.