IMO you will need a whole lot more heat than that. I heat my small pond
(about 2000 gallons) in the Richmond Virginia area with a 15 amp immersion
heater unit, and cover the pond with a lean-to greenhouse made with several
layers of polyethylene sheeting to keep the cold air and wind away form the
pond. The 4000 gallon pond uses 2 of these heaters.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"Heather" wrote in message
.. .
I had an idea and wondered if anyone had tried this.

My pond is 1800 gal.

Pump pushed uphill through a UV filter then onto a garbage can filter with
lava rock.

Gravity feeds back to 3' x 4' x 8" pond that starts the waterfall and back
to the pond.

The idea is ---- Can I either wrap the pipes with eavestrough heater
cable
or put the cable into the filter to enable the system to be left on all
winter? I thought of also laying some down the stream.

Thoughts???