CanadianCowboy© wrote:

We are in southern Ontario and although it has been above freezing there
is still a risk of snow on any given day. Is it still safe to turn on
the BIO and put in the plants (hardy water lilies)?

Sure. At this point, you're not going to give the fish a chill - you're not
going to get much activity in a bio-filter, either, but the sooner you get
it working, the better.

When I lived in St. Thomas, the hardy lilies never came _out_ of the pond
for winter.
--
derek