Gardens Bio filters
what point in cold weather are bio filters on ponds no longer effective
due to the low temperature?
nitrifying bacteria that purify pond water in a biological filter
are active down to about 4°C. If you live in the North Island, then
you will not need to worry about this at all. If you live in Invercargill
then your filter probably ceased operating efficiently back in February.
However, I generally
recommend leaving bio filters running all year. If your area experiences
deep frosts though, you should definitely disconnect and take inside
your UV filter as the cold can crack the quartz glass sleeve.
Gardener, Issue 104, 2002, Page 20
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.