I have always heard that it's best NOT to leave the filter/pump running
during the colder months. Supposedly this is to avoid having super-cold
water circulated throughout the pond. However, I also know that a lot of
people say they leave their pumps/waterfalls running all winter because it
keeps an open area (non-ice) for gas/oxygen exchange.

As for me, I have NO running water in either pond during the winter. I use
a small pond de-icer to keep a hole opened if it ices over.

--
G.D.Smith
Harpers Ferry, WV

FOR SALE: 2005 Mercedes-Benz SLK350
http://ICanHelp56.homestead.com/MB_SLK350_01.html



"fire fly" wrote in message
...
I'm new to ponding and very new to pond filters.

I've got a cheap pond filter which incorporates a UV lamp, some foam and
some rocks. Water is pumped from the fountain through the filter and back
into the pond. I have 7 smallish fish in a 400 gallon pond.

My question is this - do I need to keep the filter running 24/7 during the
winter? I live in London. Mild winters, average overnight min -4deg C,
average day temp 5-10deg C

Nick