Sera Glass cylinder for 250+UV/400+UV E

A glass cylinder for the UV-C unit. Two seal rings are included.

What it fits: according to the manufacturer's spare parts list, the sera fil bioactive 250 + UV, fil bioactive 400 + UV and sera UVC-Xtreme 800/1200.

What it does: the cylinder is a quartz tube that separates the UV-C lamp from the flowing water. The lamp burns dry inside the tube and the radiation passes through the glass into the water. If the cylinder cracks, water reaches the lamp – the unit must then be unplugged at once.

When to change it: besides breakage, when the glass has clouded with limescale or biofilm to the point where it can no longer be cleaned. A clouded cylinder passes only part of the radiation, so the whole UV-C unit gradually loses its effect and nothing on the device indicates it. The seals are worth changing at the same time, which is why they are in the pack.