Our mission: ‘To encourage and improve horticulture in NZ by promoting the understanding, appreciation, conservation and use of plants’.
Plant Doctor Archive
Water Gardens — UV clarifier

SHOULD
I switch off my UV clarifier during winter, as recommended by the
manufacturer, and bring it inside?
IT depends entirely on where you
live in New Zealand. The reason that pond equipment manufacturers
advise that the units be brought inside is that severely cold
weather (we’re talking about freezing temperatures, with ice and
snow) can cause the quartz glass sleeve to split and they are
expensive to replace.
Also, ponds are unlikely to go green in winter and turning them off will extend the bulb life.
In Auckland it is unlikely to get cold enough to warrant this procedure (I hope not anyway!) and many modern UV filters have a Teflon sleeve, so I leave it to you to make your own decision.
Weekend Gardener, Issue 99, 2002, Page 20

