The cover needs to be supported above the surface of the water to allow for
the gas exchanges. The dead air above the pond is one type of insulation,
the cover acts as a wind break, and a barrier to the exchange of warm air
with the cold air outside. The ground temperature, at about 1 or 2 feet
below the frost line is a fairly constant temperature in the low to mid
50's. This heat from the ground is transported into the pond and keeps the
pond warming. The amount of insulation at the top should be enough to
prevent freezing of the pond. Also the cover acts like a greenhouse and
allows for some solar heating if it is not covered in snow. If it is
covered in snow, then the snow is another good layer of insulation, helping
to keep the pond warm.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html
"bjt" wrote in message
...
I'm curious about people putting what sounds like pool covers over their
ponds to keep the heat in and prevent evaporative cooling. Here in New
England my pond (4-5 foot deep) gets a 1-2 foot layer of solid ice over
most
of the surface (except where I actively prevent it). So, won't any sort
of
pond cover just get frozen into the ice eventually?
Brian Tarbox
"~ jan JJsPond.us" wrote in message
...
The big advantage however is keeping my filter system up & running, as
I'm
100% convinced that one should not stop filtering a koi pond. The
bacteria
will survive, they will go dormant or perform at a very very low level,
but
they will still be there when spring kicks in.
In agreement there. I was just reading a short print out regarding this,
that the bacteria don't die, they just go dormant. I assume freezing
solid
might do them in, but with slow circulation they should hang in there.
Not
sure how I'm going to implement this with my system, but I do plan to
keep
some of the bio-foam in operation this season some how.
I just wished I'd read it earlier as I could have cleaned some of the
bio-foam earlier when it was warmer. ~ jan
See my ponds thru the seasons and/or my filter design:
http://users.owt.com/jjspond/
~Keep 'em Defrosted~
Tri-Cities, WA Zone 7a
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