The frost line is outside where the soil is exposed. Crawl spaces under
houses don't freeze. I suspect that if the pond is kept covered, the soil
under the pond would not cool significantly below the 55 degrees. The soil
around the sides would develop frost, but the pond would be heating the
soil. If the cover extends a couple of feet from the pond edge, then the
heat transfer would be slow.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html
"MC" wrote in message
om...
I believe the frostline in Chicago is 36" meaning that the ground
freezes up to 36 below ground. In zone 7 I could see the ground
staying 55 degrees, but not here.

"RichToyBox" wrote in message
news:vLqAc.47756$Hg2.30050@attbi_s04...
You may be surprised at the temperature of the pond from 500 watt
heater.
First if the pond is protected from evaporation and allowed some solar
heat,
it will supply heat to the soil, until it drops to about 55 degrees, and
then it starts being heated by the natural ground temperature, which is
a
fairly constant 55 degrees. So the heater should be raising the
temperature
from the 55 degree level, and all of your heat losses should be through
the
cover.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html
"MC" wrote in message
om...
The price range seems to run the gambit- 500W from $40 to $500+.

As I understand it, roughly each Watt will raise 1 gallon of water 10
degrees. So if my cover keeps my 500 gallon pond at a minimum of 40
degrees, a 500W heater will raise it to 50 degrees.


wrote in message
...
p. 361 of aquatic ecosystems catalog, $44 and extra 30 for the
controller. but they
got titanium that are cheaper. mine has a separate temperature probe
and
the heater
is covered to prevent it from getting hit or melting liner down.
people
in warmer
zones dont understand that our ponds drop below 50o (when koi's
immune
system goes
down and feeding stops) sometime mid october in zone 5 and doesnt
rise
over 50o until
mid april. that is 6 months of no immunity and 6 months of no food.
it
is VERY VERY
hard on koi. you can always order some kind of pool from aquatic
ecosystem, or,
build a stud wall pond in the basement and line that with permalon.
Ingrid

(MC) wrote:
What kind of heater are you using? I've heard of people using
trough
heaters and there seems to be several kinds of pond heaters. I only
have 500 gallons in Chicago.

It is early, but my first year I lost all my Koi (used a bubbler to
keep hole open). Last winter, I brought them inside. They are now
kind
of big to bring inside. I am trying to plan ahead. If I need to
bring
them inside this winter, I need to buy a kiddie pool and you can't
find them in the winter in Chicago.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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http://puregold.aquaria.net/
www.drsolo.com
Solve the problem, dont waste energy finding who's to blame
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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