Hi Rob,

You wrote Do I have to have an opening in the ice for gases to escape? Should
I heat
the bottom of the pond or the surface?

Yes, you are going to want to keep an opening in the ice to keep your crew
alive.
There are floating pond heaters, they come on at a certain temperature and
heat just the area around them.
Or you can run an air pump with a bubbler attached. The agitation keeps a hole
open. (I attached my air pump to the post my electrical box is on and then
covered it with an upside down tub to keep it out of the elements.)
Some folks disconnect their pump and put it under the surface of the water and
keep the hole open that way.

Energy usage is important. I think the least expensive way is to run a bubbler
but I could be wrong. Anyone know? We have some Canadians online who can chime
in with what they do.


kathy :-)
algae primer
http://hometown.aol.com/ka30p/myhomepage/garden.html